diff --git a/src/Polly/Caching/AsyncCacheEngine.cs b/src/Polly/Caching/AsyncCacheEngine.cs
index 1e4657e4c84..4ef9dcc1c09 100644
--- a/src/Polly/Caching/AsyncCacheEngine.cs
+++ b/src/Polly/Caching/AsyncCacheEngine.cs
@@ -14,8 +14,8 @@ internal static async Task<TResult> ImplementationAsync<TResult>(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError)
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError)
     {
         cancellationToken.ThrowIfCancellationRequested();
 
@@ -35,7 +35,7 @@ internal static async Task<TResult> ImplementationAsync<TResult>(
         {
             cacheHit = false;
             valueFromCache = default;
-            onCacheGetError(context, cacheKey, ex);
+            onCacheGetError?.Invoke(context, cacheKey, ex);
         }
         if (cacheHit)
         {
@@ -59,7 +59,7 @@ internal static async Task<TResult> ImplementationAsync<TResult>(
             }
             catch (Exception ex)
             {
-                onCachePutError(context, cacheKey, ex);
+                onCachePutError?.Invoke(context, cacheKey, ex);
             }
         }
 
diff --git a/src/Polly/Caching/AsyncCachePolicy.cs b/src/Polly/Caching/AsyncCachePolicy.cs
index c4fccfa9809..a79aeafe486 100644
--- a/src/Polly/Caching/AsyncCachePolicy.cs
+++ b/src/Polly/Caching/AsyncCachePolicy.cs
@@ -1,4 +1,5 @@
-namespace Polly.Caching;
+#nullable enable
+namespace Polly.Caching;
 
 /// <summary>
 /// A cache policy that can be applied to the results of delegate executions.
@@ -12,8 +13,8 @@ public class AsyncCachePolicy : AsyncPolicy
     private readonly Action<Context, string> _onCacheGet;
     private readonly Action<Context, string> _onCacheMiss;
     private readonly Action<Context, string> _onCachePut;
-    private readonly Action<Context, string, Exception> _onCacheGetError;
-    private readonly Action<Context, string, Exception> _onCachePutError;
+    private readonly Action<Context, string, Exception>? _onCacheGetError;
+    private readonly Action<Context, string, Exception>? _onCachePutError;
 
     internal AsyncCachePolicy(
         IAsyncCacheProvider asyncCacheProvider,
@@ -22,8 +23,8 @@ internal AsyncCachePolicy(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError)
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError)
     {
         _asyncCacheProvider = asyncCacheProvider;
         _ttlStrategy = ttlStrategy;
@@ -77,8 +78,8 @@ public class AsyncCachePolicy<TResult> : AsyncPolicy<TResult>
     private readonly Action<Context, string> _onCacheGet;
     private readonly Action<Context, string> _onCacheMiss;
     private readonly Action<Context, string> _onCachePut;
-    private readonly Action<Context, string, Exception> _onCacheGetError;
-    private readonly Action<Context, string, Exception> _onCachePutError;
+    private readonly Action<Context, string, Exception>? _onCacheGetError;
+    private readonly Action<Context, string, Exception>? _onCachePutError;
 
     internal AsyncCachePolicy(
         IAsyncCacheProvider<TResult> asyncCacheProvider,
@@ -87,8 +88,8 @@ internal AsyncCachePolicy(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError)
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError)
     {
         _asyncCacheProvider = asyncCacheProvider;
         _ttlStrategy = ttlStrategy;
diff --git a/src/Polly/Caching/AsyncCacheSyntax.cs b/src/Polly/Caching/AsyncCacheSyntax.cs
index ec7a9e9375a..7353ad46939 100644
--- a/src/Polly/Caching/AsyncCacheSyntax.cs
+++ b/src/Polly/Caching/AsyncCacheSyntax.cs
@@ -68,7 +68,6 @@ public static AsyncCachePolicy CacheAsync(IAsyncCacheProvider cacheProvider, ITt
         if (ttlStrategy == null) throw new ArgumentNullException(nameof(ttlStrategy));
         if (cacheKeyStrategy == null) throw new ArgumentNullException(nameof(cacheKeyStrategy));
 
-        onCacheError ??= (_, _, _) => { };
         Action<Context, string> emptyDelegate = (_, _) => { };
 
         return new AsyncCachePolicy(cacheProvider, ttlStrategy, cacheKeyStrategy.GetCacheKey, emptyDelegate, emptyDelegate, emptyDelegate, onCacheError, onCacheError);
@@ -110,7 +109,6 @@ public static AsyncCachePolicy CacheAsync(IAsyncCacheProvider cacheProvider, ITt
         if (ttlStrategy == null) throw new ArgumentNullException(nameof(ttlStrategy));
         if (cacheKeyStrategy == null) throw new ArgumentNullException(nameof(cacheKeyStrategy));
 
-        onCacheError ??= (_, _, _) => { };
         Action<Context, string> emptyDelegate = (_, _) => { };
 
         return new AsyncCachePolicy(cacheProvider, ttlStrategy, cacheKeyStrategy, emptyDelegate, emptyDelegate, emptyDelegate, onCacheError, onCacheError);
@@ -134,16 +132,14 @@ public static AsyncCachePolicy CacheAsync(IAsyncCacheProvider cacheProvider, ITt
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static AsyncCachePolicy CacheAsync(
         IAsyncCacheProvider cacheProvider,
         TimeSpan ttl,
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError) =>
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError) =>
         CacheAsync(cacheProvider, new RelativeTtl(ttl), DefaultCacheKeyStrategy.Instance.GetCacheKey, onCacheGet, onCacheMiss, onCachePut, onCacheGetError, onCachePutError);
 
     /// <summary>
@@ -165,16 +161,14 @@ public static AsyncCachePolicy CacheAsync(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static AsyncCachePolicy CacheAsync(
         IAsyncCacheProvider cacheProvider,
         ITtlStrategy ttlStrategy,
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError) =>
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError) =>
         CacheAsync(cacheProvider, ttlStrategy, DefaultCacheKeyStrategy.Instance.GetCacheKey, onCacheGet, onCacheMiss, onCachePut, onCacheGetError, onCachePutError);
 
     /// <summary>
@@ -197,8 +191,6 @@ public static AsyncCachePolicy CacheAsync(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static AsyncCachePolicy CacheAsync(
         IAsyncCacheProvider cacheProvider,
         TimeSpan ttl,
@@ -206,8 +198,8 @@ public static AsyncCachePolicy CacheAsync(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError) =>
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError) =>
         CacheAsync(cacheProvider, new RelativeTtl(ttl), cacheKeyStrategy.GetCacheKey, onCacheGet, onCacheMiss, onCachePut, onCacheGetError, onCachePutError);
 
     /// <summary>
@@ -231,8 +223,6 @@ public static AsyncCachePolicy CacheAsync(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static AsyncCachePolicy CacheAsync(
         IAsyncCacheProvider cacheProvider,
         ITtlStrategy ttlStrategy,
@@ -240,8 +230,8 @@ public static AsyncCachePolicy CacheAsync(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError) =>
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError) =>
         CacheAsync(cacheProvider, ttlStrategy, cacheKeyStrategy.GetCacheKey, onCacheGet, onCacheMiss, onCachePut, onCacheGetError, onCachePutError);
 
     /// <summary>
@@ -264,8 +254,6 @@ public static AsyncCachePolicy CacheAsync(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static AsyncCachePolicy CacheAsync(
         IAsyncCacheProvider cacheProvider,
         TimeSpan ttl,
@@ -273,8 +261,8 @@ public static AsyncCachePolicy CacheAsync(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError) =>
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError) =>
         CacheAsync(cacheProvider, new RelativeTtl(ttl), cacheKeyStrategy, onCacheGet, onCacheMiss, onCachePut, onCacheGetError, onCachePutError);
 
     /// <summary>
@@ -298,8 +286,6 @@ public static AsyncCachePolicy CacheAsync(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static AsyncCachePolicy CacheAsync(
         IAsyncCacheProvider cacheProvider,
         ITtlStrategy ttlStrategy,
@@ -307,8 +293,8 @@ public static AsyncCachePolicy CacheAsync(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError)
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError)
     {
         if (cacheProvider == null) throw new ArgumentNullException(nameof(cacheProvider));
         if (ttlStrategy == null) throw new ArgumentNullException(nameof(ttlStrategy));
@@ -317,8 +303,6 @@ public static AsyncCachePolicy CacheAsync(
         if (onCacheGet == null) throw new ArgumentNullException(nameof(onCacheGet));
         if (onCacheMiss == null) throw new ArgumentNullException(nameof(onCacheMiss));
         if (onCachePut == null) throw new ArgumentNullException(nameof(onCachePut));
-        if (onCacheGetError == null) throw new ArgumentNullException(nameof(onCacheGetError));
-        if (onCachePutError == null) throw new ArgumentNullException(nameof(onCachePutError));
 
         return new AsyncCachePolicy(cacheProvider, ttlStrategy, cacheKeyStrategy, onCacheGet, onCacheMiss, onCachePut, onCacheGetError, onCachePutError);
     }
diff --git a/src/Polly/Caching/AsyncCacheTResultSyntax.cs b/src/Polly/Caching/AsyncCacheTResultSyntax.cs
index e0d859986a1..da92d36c82a 100644
--- a/src/Polly/Caching/AsyncCacheTResultSyntax.cs
+++ b/src/Polly/Caching/AsyncCacheTResultSyntax.cs
@@ -140,16 +140,14 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(IAsyncCacheProvider
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
         IAsyncCacheProvider cacheProvider,
         TimeSpan ttl,
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError)
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError)
     {
         if (cacheProvider == null) throw new ArgumentNullException(nameof(cacheProvider));
 
@@ -175,16 +173,14 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
         IAsyncCacheProvider cacheProvider,
         ITtlStrategy ttlStrategy,
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError)
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError)
     {
         if (cacheProvider == null) throw new ArgumentNullException(nameof(cacheProvider));
 
@@ -211,8 +207,6 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
         IAsyncCacheProvider cacheProvider,
         TimeSpan ttl,
@@ -220,8 +214,8 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError)
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError)
     {
         if (cacheProvider == null) throw new ArgumentNullException(nameof(cacheProvider));
 
@@ -249,8 +243,6 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
         IAsyncCacheProvider cacheProvider,
         ITtlStrategy ttlStrategy,
@@ -258,8 +250,8 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError)
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError)
     {
         if (cacheProvider == null) throw new ArgumentNullException(nameof(cacheProvider));
 
@@ -286,8 +278,6 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
         IAsyncCacheProvider cacheProvider,
         TimeSpan ttl,
@@ -295,8 +285,8 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError)
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError)
     {
         if (cacheProvider == null) throw new ArgumentNullException(nameof(cacheProvider));
 
@@ -324,8 +314,6 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
         IAsyncCacheProvider cacheProvider,
         ITtlStrategy ttlStrategy,
@@ -333,8 +321,8 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError)
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError)
     {
         if (cacheProvider == null) throw new ArgumentNullException(nameof(cacheProvider));
 
@@ -417,8 +405,6 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(IAsyncCacheProvider<
     /// <exception cref="ArgumentNullException">cacheKeyStrategy</exception>
     public static AsyncCachePolicy<TResult> CacheAsync<TResult>(IAsyncCacheProvider<TResult> cacheProvider, ITtlStrategy ttlStrategy, ICacheKeyStrategy cacheKeyStrategy, Action<Context, string, Exception>? onCacheError = null)
     {
-        onCacheError ??= (_, _, _) => { };
-
         Action<Context, string> emptyDelegate = (_, _) => { };
 
         return CacheAsync<TResult>(cacheProvider, ttlStrategy, cacheKeyStrategy.GetCacheKey, emptyDelegate, emptyDelegate, emptyDelegate, onCacheError, onCacheError);
@@ -440,8 +426,6 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(IAsyncCacheProvider<
     /// <exception cref="ArgumentNullException">cacheKeyStrategy</exception>
     public static AsyncCachePolicy<TResult> CacheAsync<TResult>(IAsyncCacheProvider<TResult> cacheProvider, ITtlStrategy<TResult> ttlStrategy, ICacheKeyStrategy cacheKeyStrategy, Action<Context, string, Exception>? onCacheError = null)
     {
-        onCacheError ??= (_, _, _) => { };
-
         Action<Context, string> emptyDelegate = (_, _) => { };
 
         return CacheAsync<TResult>(cacheProvider, ttlStrategy, cacheKeyStrategy.GetCacheKey, emptyDelegate, emptyDelegate, emptyDelegate, onCacheError, onCacheError);
@@ -479,8 +463,6 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(IAsyncCacheProvider<
     /// <exception cref="ArgumentNullException">cacheKeyStrategy</exception>
     public static AsyncCachePolicy<TResult> CacheAsync<TResult>(IAsyncCacheProvider<TResult> cacheProvider, ITtlStrategy ttlStrategy, Func<Context, string> cacheKeyStrategy, Action<Context, string, Exception>? onCacheError = null)
     {
-        onCacheError ??= (_, _, _) => { };
-
         Action<Context, string> emptyDelegate = (_, _) => { };
 
         return CacheAsync<TResult>(cacheProvider, ttlStrategy, cacheKeyStrategy, emptyDelegate, emptyDelegate, emptyDelegate, onCacheError, onCacheError);
@@ -502,8 +484,6 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(IAsyncCacheProvider<
     /// <exception cref="ArgumentNullException">cacheKeyStrategy</exception>
     public static AsyncCachePolicy<TResult> CacheAsync<TResult>(IAsyncCacheProvider<TResult> cacheProvider, ITtlStrategy<TResult> ttlStrategy, Func<Context, string> cacheKeyStrategy, Action<Context, string, Exception>? onCacheError = null)
     {
-        onCacheError ??= (_, _, _) => { };
-
         Action<Context, string> emptyDelegate = (_, _) => { };
 
         return CacheAsync<TResult>(cacheProvider, ttlStrategy, cacheKeyStrategy, emptyDelegate, emptyDelegate, emptyDelegate, onCacheError, onCacheError);
@@ -527,16 +507,14 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(IAsyncCacheProvider<
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
         IAsyncCacheProvider<TResult> cacheProvider,
         TimeSpan ttl,
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError) =>
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError) =>
         CacheAsync<TResult>(cacheProvider, new RelativeTtl(ttl), DefaultCacheKeyStrategy.Instance.GetCacheKey, onCacheGet, onCacheMiss,
             onCachePut, onCacheGetError, onCachePutError);
 
@@ -559,16 +537,14 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
         IAsyncCacheProvider<TResult> cacheProvider,
         ITtlStrategy ttlStrategy,
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError) =>
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError) =>
         CacheAsync<TResult>(cacheProvider, ttlStrategy.For<TResult>(), DefaultCacheKeyStrategy.Instance.GetCacheKey, onCacheGet, onCacheMiss, onCachePut, onCacheGetError, onCachePutError);
 
     /// <summary>
@@ -590,16 +566,14 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
         IAsyncCacheProvider<TResult> cacheProvider,
         ITtlStrategy<TResult> ttlStrategy,
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError) =>
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError) =>
         CacheAsync<TResult>(cacheProvider, ttlStrategy, DefaultCacheKeyStrategy.Instance.GetCacheKey, onCacheGet, onCacheMiss, onCachePut, onCacheGetError, onCachePutError);
 
     /// <summary>
@@ -622,8 +596,6 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
         IAsyncCacheProvider<TResult> cacheProvider,
         TimeSpan ttl,
@@ -631,8 +603,8 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError) =>
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError) =>
         CacheAsync<TResult>(cacheProvider, new RelativeTtl(ttl), cacheKeyStrategy.GetCacheKey, onCacheGet, onCacheMiss,
             onCachePut, onCacheGetError, onCachePutError);
 
@@ -657,8 +629,6 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
         IAsyncCacheProvider<TResult> cacheProvider,
         ITtlStrategy ttlStrategy,
@@ -666,8 +636,8 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError) =>
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError) =>
         CacheAsync<TResult>(cacheProvider, ttlStrategy.For<TResult>(), cacheKeyStrategy.GetCacheKey, onCacheGet, onCacheMiss, onCachePut, onCacheGetError, onCachePutError);
 
     /// <summary>
@@ -691,8 +661,6 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
         IAsyncCacheProvider<TResult> cacheProvider,
         ITtlStrategy<TResult> ttlStrategy,
@@ -700,8 +668,8 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError) =>
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError) =>
         CacheAsync<TResult>(cacheProvider, ttlStrategy, cacheKeyStrategy.GetCacheKey, onCacheGet, onCacheMiss, onCachePut, onCacheGetError, onCachePutError);
 
     /// <summary>
@@ -724,8 +692,6 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
         IAsyncCacheProvider<TResult> cacheProvider,
         TimeSpan ttl,
@@ -733,8 +699,8 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError) =>
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError) =>
         CacheAsync<TResult>(cacheProvider, new RelativeTtl(ttl), cacheKeyStrategy, onCacheGet, onCacheMiss,
             onCachePut, onCacheGetError, onCachePutError);
 
@@ -759,8 +725,6 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
         IAsyncCacheProvider<TResult> cacheProvider,
         ITtlStrategy ttlStrategy,
@@ -768,8 +732,8 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError) =>
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError) =>
         CacheAsync<TResult>(cacheProvider, ttlStrategy.For<TResult>(), cacheKeyStrategy, onCacheGet, onCacheMiss, onCachePut, onCacheGetError, onCachePutError);
 
     /// <summary>
@@ -793,8 +757,6 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
         IAsyncCacheProvider<TResult> cacheProvider,
         ITtlStrategy<TResult> ttlStrategy,
@@ -802,8 +764,8 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError)
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError)
     {
         if (cacheProvider == null) throw new ArgumentNullException(nameof(cacheProvider));
         if (ttlStrategy == null) throw new ArgumentNullException(nameof(ttlStrategy));
@@ -812,8 +774,6 @@ public static AsyncCachePolicy<TResult> CacheAsync<TResult>(
         if (onCacheGet == null) throw new ArgumentNullException(nameof(onCacheGet));
         if (onCacheMiss == null) throw new ArgumentNullException(nameof(onCacheMiss));
         if (onCachePut == null) throw new ArgumentNullException(nameof(onCachePut));
-        if (onCacheGetError == null) throw new ArgumentNullException(nameof(onCacheGetError));
-        if (onCachePutError == null) throw new ArgumentNullException(nameof(onCachePutError));
 
         return new AsyncCachePolicy<TResult>(cacheProvider, ttlStrategy, cacheKeyStrategy, onCacheGet, onCacheMiss, onCachePut, onCacheGetError, onCachePutError);
     }
diff --git a/src/Polly/Caching/CacheEngine.cs b/src/Polly/Caching/CacheEngine.cs
index 493b5207d4a..ca2a1a469e1 100644
--- a/src/Polly/Caching/CacheEngine.cs
+++ b/src/Polly/Caching/CacheEngine.cs
@@ -13,8 +13,8 @@ internal static TResult Implementation<TResult>(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError)
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError)
     {
         cancellationToken.ThrowIfCancellationRequested();
 
@@ -34,7 +34,7 @@ internal static TResult Implementation<TResult>(
         {
             cacheHit = false;
             valueFromCache = default;
-            onCacheGetError(context, cacheKey, ex);
+            onCacheGetError?.Invoke(context, cacheKey, ex);
         }
         if (cacheHit)
         {
@@ -58,7 +58,7 @@ internal static TResult Implementation<TResult>(
             }
             catch (Exception ex)
             {
-                onCachePutError(context, cacheKey, ex);
+                onCachePutError?.Invoke(context, cacheKey, ex);
             }
         }
 
diff --git a/src/Polly/Caching/CachePolicy.cs b/src/Polly/Caching/CachePolicy.cs
index e775ce62a0f..762bcf9273d 100644
--- a/src/Polly/Caching/CachePolicy.cs
+++ b/src/Polly/Caching/CachePolicy.cs
@@ -1,4 +1,5 @@
-namespace Polly.Caching;
+#nullable enable
+namespace Polly.Caching;
 
 /// <summary>
 /// A cache policy that can be applied to the results of delegate executions.
@@ -12,8 +13,8 @@ public class CachePolicy : Policy, ICachePolicy
     private readonly Action<Context, string> _onCacheGet;
     private readonly Action<Context, string> _onCacheMiss;
     private readonly Action<Context, string> _onCachePut;
-    private readonly Action<Context, string, Exception> _onCacheGetError;
-    private readonly Action<Context, string, Exception> _onCachePutError;
+    private readonly Action<Context, string, Exception>? _onCacheGetError;
+    private readonly Action<Context, string, Exception>? _onCachePutError;
 
     internal CachePolicy(
         ISyncCacheProvider syncCacheProvider,
@@ -22,8 +23,8 @@ internal CachePolicy(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError)
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError)
     {
         _syncCacheProvider = syncCacheProvider;
         _ttlStrategy = ttlStrategy;
@@ -70,8 +71,8 @@ public class CachePolicy<TResult> : Policy<TResult>, ICachePolicy<TResult>
     private readonly Action<Context, string> _onCacheGet;
     private readonly Action<Context, string> _onCacheMiss;
     private readonly Action<Context, string> _onCachePut;
-    private readonly Action<Context, string, Exception> _onCacheGetError;
-    private readonly Action<Context, string, Exception> _onCachePutError;
+    private readonly Action<Context, string, Exception>? _onCacheGetError;
+    private readonly Action<Context, string, Exception>? _onCachePutError;
 
     internal CachePolicy(
         ISyncCacheProvider<TResult> syncCacheProvider,
@@ -80,8 +81,8 @@ internal CachePolicy(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError)
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError)
     {
         _syncCacheProvider = syncCacheProvider;
         _ttlStrategy = ttlStrategy;
diff --git a/src/Polly/Caching/CacheSyntax.cs b/src/Polly/Caching/CacheSyntax.cs
index b02af77a3b2..d104ed2d98a 100644
--- a/src/Polly/Caching/CacheSyntax.cs
+++ b/src/Polly/Caching/CacheSyntax.cs
@@ -68,7 +68,6 @@ public static CachePolicy Cache(ISyncCacheProvider cacheProvider, ITtlStrategy t
         if (ttlStrategy == null) throw new ArgumentNullException(nameof(ttlStrategy));
         if (cacheKeyStrategy == null) throw new ArgumentNullException(nameof(cacheKeyStrategy));
 
-        onCacheError ??= (_, _, _) => { };
         Action<Context, string> emptyDelegate = (_, _) => { };
 
         return Cache(cacheProvider, ttlStrategy, cacheKeyStrategy.GetCacheKey, emptyDelegate, emptyDelegate, emptyDelegate, onCacheError, onCacheError);
@@ -110,7 +109,6 @@ public static CachePolicy Cache(ISyncCacheProvider cacheProvider, ITtlStrategy t
         if (ttlStrategy == null) throw new ArgumentNullException(nameof(ttlStrategy));
         if (cacheKeyStrategy == null) throw new ArgumentNullException(nameof(cacheKeyStrategy));
 
-        onCacheError ??= (_, _, _) => { };
         Action<Context, string> emptyDelegate = (_, _) => { };
 
         return Cache(cacheProvider, ttlStrategy, cacheKeyStrategy, emptyDelegate, emptyDelegate, emptyDelegate, onCacheError, onCacheError);
@@ -136,16 +134,14 @@ public static CachePolicy Cache(ISyncCacheProvider cacheProvider, ITtlStrategy t
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static CachePolicy Cache(
         ISyncCacheProvider cacheProvider,
         TimeSpan ttl,
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError) =>
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError) =>
         Cache(cacheProvider, new RelativeTtl(ttl), DefaultCacheKeyStrategy.Instance.GetCacheKey, onCacheGet, onCacheMiss, onCachePut, onCacheGetError, onCachePutError);
 
     /// <summary>
@@ -169,16 +165,14 @@ public static CachePolicy Cache(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static CachePolicy Cache(
         ISyncCacheProvider cacheProvider,
         ITtlStrategy ttlStrategy,
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError) =>
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError) =>
         Cache(cacheProvider, ttlStrategy, DefaultCacheKeyStrategy.Instance.GetCacheKey, onCacheGet, onCacheMiss, onCachePut, onCacheGetError, onCachePutError);
 
     /// <summary>
@@ -203,8 +197,6 @@ public static CachePolicy Cache(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static CachePolicy Cache(
         ISyncCacheProvider cacheProvider,
         TimeSpan ttl,
@@ -212,8 +204,8 @@ public static CachePolicy Cache(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError) =>
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError) =>
         Cache(cacheProvider, new RelativeTtl(ttl), cacheKeyStrategy.GetCacheKey, onCacheGet, onCacheMiss, onCachePut, onCacheGetError, onCachePutError);
 
     /// <summary>
@@ -239,8 +231,6 @@ public static CachePolicy Cache(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static CachePolicy Cache(
         ISyncCacheProvider cacheProvider,
         ITtlStrategy ttlStrategy,
@@ -248,8 +238,8 @@ public static CachePolicy Cache(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError) =>
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError) =>
         Cache(cacheProvider, ttlStrategy, cacheKeyStrategy.GetCacheKey, onCacheGet, onCacheMiss, onCachePut, onCacheGetError, onCachePutError);
 
     /// <summary>
@@ -274,8 +264,6 @@ public static CachePolicy Cache(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static CachePolicy Cache(
         ISyncCacheProvider cacheProvider,
         TimeSpan ttl,
@@ -283,8 +271,8 @@ public static CachePolicy Cache(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError) =>
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError) =>
         Cache(cacheProvider, new RelativeTtl(ttl), cacheKeyStrategy, onCacheGet, onCacheMiss, onCachePut, onCacheGetError, onCachePutError);
 
     /// <summary>
@@ -310,8 +298,6 @@ public static CachePolicy Cache(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static CachePolicy Cache(
         ISyncCacheProvider cacheProvider,
         ITtlStrategy ttlStrategy,
@@ -319,8 +305,8 @@ public static CachePolicy Cache(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError)
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError)
     {
         if (cacheProvider == null) throw new ArgumentNullException(nameof(cacheProvider));
         if (ttlStrategy == null) throw new ArgumentNullException(nameof(ttlStrategy));
@@ -329,8 +315,6 @@ public static CachePolicy Cache(
         if (onCacheGet == null) throw new ArgumentNullException(nameof(onCacheGet));
         if (onCacheMiss == null) throw new ArgumentNullException(nameof(onCacheMiss));
         if (onCachePut == null) throw new ArgumentNullException(nameof(onCachePut));
-        if (onCacheGetError == null) throw new ArgumentNullException(nameof(onCacheGetError));
-        if (onCachePutError == null) throw new ArgumentNullException(nameof(onCachePutError));
 
         return new CachePolicy(cacheProvider, ttlStrategy, cacheKeyStrategy, onCacheGet, onCacheMiss, onCachePut, onCacheGetError, onCachePutError);
     }
diff --git a/src/Polly/Caching/CacheTResultSyntax.cs b/src/Polly/Caching/CacheTResultSyntax.cs
index de9c80606ef..9e3ed6666d0 100644
--- a/src/Polly/Caching/CacheTResultSyntax.cs
+++ b/src/Polly/Caching/CacheTResultSyntax.cs
@@ -140,16 +140,14 @@ public static CachePolicy<TResult> Cache<TResult>(ISyncCacheProvider cacheProvid
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static CachePolicy<TResult> Cache<TResult>(
         ISyncCacheProvider cacheProvider,
         TimeSpan ttl,
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError)
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError)
     {
         if (cacheProvider == null) throw new ArgumentNullException(nameof(cacheProvider));
 
@@ -175,16 +173,14 @@ public static CachePolicy<TResult> Cache<TResult>(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static CachePolicy<TResult> Cache<TResult>(
         ISyncCacheProvider cacheProvider,
         ITtlStrategy ttlStrategy,
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError)
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError)
     {
         if (cacheProvider == null) throw new ArgumentNullException(nameof(cacheProvider));
 
@@ -211,8 +207,6 @@ public static CachePolicy<TResult> Cache<TResult>(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static CachePolicy<TResult> Cache<TResult>(
         ISyncCacheProvider cacheProvider,
         TimeSpan ttl,
@@ -220,8 +214,8 @@ public static CachePolicy<TResult> Cache<TResult>(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError)
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError)
     {
         if (cacheProvider == null) throw new ArgumentNullException(nameof(cacheProvider));
 
@@ -249,8 +243,6 @@ public static CachePolicy<TResult> Cache<TResult>(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static CachePolicy<TResult> Cache<TResult>(
         ISyncCacheProvider cacheProvider,
         ITtlStrategy ttlStrategy,
@@ -258,8 +250,8 @@ public static CachePolicy<TResult> Cache<TResult>(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError)
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError)
     {
         if (cacheProvider == null) throw new ArgumentNullException(nameof(cacheProvider));
 
@@ -286,8 +278,6 @@ public static CachePolicy<TResult> Cache<TResult>(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static CachePolicy<TResult> Cache<TResult>(
         ISyncCacheProvider cacheProvider,
         TimeSpan ttl,
@@ -295,8 +285,8 @@ public static CachePolicy<TResult> Cache<TResult>(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError)
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError)
     {
         if (cacheProvider == null) throw new ArgumentNullException(nameof(cacheProvider));
 
@@ -324,8 +314,6 @@ public static CachePolicy<TResult> Cache<TResult>(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static CachePolicy<TResult> Cache<TResult>(
         ISyncCacheProvider cacheProvider,
         ITtlStrategy ttlStrategy,
@@ -333,8 +321,8 @@ public static CachePolicy<TResult> Cache<TResult>(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError)
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError)
     {
         if (cacheProvider == null) throw new ArgumentNullException(nameof(cacheProvider));
 
@@ -417,8 +405,6 @@ public static CachePolicy<TResult> Cache<TResult>(ISyncCacheProvider<TResult> ca
     /// <exception cref="ArgumentNullException">cacheKeyStrategy</exception>
     public static CachePolicy<TResult> Cache<TResult>(ISyncCacheProvider<TResult> cacheProvider, ITtlStrategy ttlStrategy, ICacheKeyStrategy cacheKeyStrategy, Action<Context, string, Exception>? onCacheError = null)
     {
-        onCacheError ??= (_, _, _) => { };
-
         Action<Context, string> emptyDelegate = (_, _) => { };
 
         return Cache<TResult>(cacheProvider, ttlStrategy.For<TResult>(), cacheKeyStrategy.GetCacheKey,
@@ -441,8 +427,6 @@ public static CachePolicy<TResult> Cache<TResult>(ISyncCacheProvider<TResult> ca
     /// <exception cref="ArgumentNullException">cacheKeyStrategy</exception>
     public static CachePolicy<TResult> Cache<TResult>(ISyncCacheProvider<TResult> cacheProvider, ITtlStrategy<TResult> ttlStrategy, ICacheKeyStrategy cacheKeyStrategy, Action<Context, string, Exception>? onCacheError = null)
     {
-        onCacheError ??= (_, _, _) => { };
-
         Action<Context, string> emptyDelegate = (_, _) => { };
 
         return Cache(cacheProvider, ttlStrategy, cacheKeyStrategy, emptyDelegate, emptyDelegate, emptyDelegate,
@@ -481,8 +465,6 @@ public static CachePolicy<TResult> Cache<TResult>(ISyncCacheProvider<TResult> ca
     /// <exception cref="ArgumentNullException">cacheKeyStrategy</exception>
     public static CachePolicy<TResult> Cache<TResult>(ISyncCacheProvider<TResult> cacheProvider, ITtlStrategy ttlStrategy, Func<Context, string> cacheKeyStrategy, Action<Context, string, Exception>? onCacheError = null)
     {
-        onCacheError ??= (_, _, _) => { };
-
         Action<Context, string> emptyDelegate = (_, _) => { };
 
         return Cache<TResult>(cacheProvider, ttlStrategy.For<TResult>(), cacheKeyStrategy,
@@ -505,8 +487,6 @@ public static CachePolicy<TResult> Cache<TResult>(ISyncCacheProvider<TResult> ca
     /// <exception cref="ArgumentNullException">cacheKeyStrategy</exception>
     public static CachePolicy<TResult> Cache<TResult>(ISyncCacheProvider<TResult> cacheProvider, ITtlStrategy<TResult> ttlStrategy, Func<Context, string> cacheKeyStrategy, Action<Context, string, Exception>? onCacheError = null)
     {
-        onCacheError ??= (_, _, _) => { };
-
         Action<Context, string> emptyDelegate = (_, _) => { };
 
         return Cache(cacheProvider, ttlStrategy, cacheKeyStrategy, emptyDelegate, emptyDelegate, emptyDelegate,
@@ -531,16 +511,14 @@ public static CachePolicy<TResult> Cache<TResult>(ISyncCacheProvider<TResult> ca
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static CachePolicy<TResult> Cache<TResult>(
         ISyncCacheProvider<TResult> cacheProvider,
         TimeSpan ttl,
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError) =>
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError) =>
         Cache<TResult>(cacheProvider, new RelativeTtl(ttl), DefaultCacheKeyStrategy.Instance.GetCacheKey, onCacheGet, onCacheMiss,
             onCachePut, onCacheGetError, onCachePutError);
 
@@ -563,16 +541,14 @@ public static CachePolicy<TResult> Cache<TResult>(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static CachePolicy<TResult> Cache<TResult>(
         ISyncCacheProvider<TResult> cacheProvider,
         ITtlStrategy ttlStrategy,
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError) =>
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError) =>
         Cache<TResult>(cacheProvider, ttlStrategy, DefaultCacheKeyStrategy.Instance.GetCacheKey, onCacheGet, onCacheMiss, onCachePut, onCacheGetError, onCachePutError);
 
     /// <summary>
@@ -594,16 +570,14 @@ public static CachePolicy<TResult> Cache<TResult>(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static CachePolicy<TResult> Cache<TResult>(
         ISyncCacheProvider<TResult> cacheProvider,
         ITtlStrategy<TResult> ttlStrategy,
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError) =>
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError) =>
         Cache<TResult>(cacheProvider, ttlStrategy, DefaultCacheKeyStrategy.Instance.GetCacheKey, onCacheGet, onCacheMiss, onCachePut, onCacheGetError, onCachePutError);
 
     /// <summary>
@@ -626,8 +600,6 @@ public static CachePolicy<TResult> Cache<TResult>(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static CachePolicy<TResult> Cache<TResult>(
         ISyncCacheProvider<TResult> cacheProvider,
         TimeSpan ttl,
@@ -635,8 +607,8 @@ public static CachePolicy<TResult> Cache<TResult>(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError) =>
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError) =>
         Cache<TResult>(cacheProvider, new RelativeTtl(ttl), cacheKeyStrategy.GetCacheKey, onCacheGet, onCacheMiss,
             onCachePut, onCacheGetError, onCachePutError);
 
@@ -661,8 +633,6 @@ public static CachePolicy<TResult> Cache<TResult>(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static CachePolicy<TResult> Cache<TResult>(
         ISyncCacheProvider<TResult> cacheProvider,
         ITtlStrategy ttlStrategy,
@@ -670,8 +640,8 @@ public static CachePolicy<TResult> Cache<TResult>(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError) =>
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError) =>
         Cache<TResult>(cacheProvider, ttlStrategy, cacheKeyStrategy.GetCacheKey, onCacheGet, onCacheMiss, onCachePut, onCacheGetError, onCachePutError);
 
     /// <summary>
@@ -695,8 +665,6 @@ public static CachePolicy<TResult> Cache<TResult>(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static CachePolicy<TResult> Cache<TResult>(
         ISyncCacheProvider<TResult> cacheProvider,
         ITtlStrategy<TResult> ttlStrategy,
@@ -704,8 +672,8 @@ public static CachePolicy<TResult> Cache<TResult>(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError) =>
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError) =>
         Cache<TResult>(cacheProvider, ttlStrategy, cacheKeyStrategy.GetCacheKey, onCacheGet, onCacheMiss, onCachePut, onCacheGetError, onCachePutError);
 
     /// <summary>
@@ -728,8 +696,6 @@ public static CachePolicy<TResult> Cache<TResult>(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static CachePolicy<TResult> Cache<TResult>(
         ISyncCacheProvider<TResult> cacheProvider,
         TimeSpan ttl,
@@ -737,8 +703,8 @@ public static CachePolicy<TResult> Cache<TResult>(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError) =>
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError) =>
         Cache<TResult>(cacheProvider, new RelativeTtl(ttl), cacheKeyStrategy, onCacheGet, onCacheMiss,
             onCachePut, onCacheGetError, onCachePutError);
 
@@ -763,8 +729,6 @@ public static CachePolicy<TResult> Cache<TResult>(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static CachePolicy<TResult> Cache<TResult>(
         ISyncCacheProvider<TResult> cacheProvider,
         ITtlStrategy ttlStrategy,
@@ -772,8 +736,8 @@ public static CachePolicy<TResult> Cache<TResult>(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError) =>
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError) =>
         Cache(cacheProvider, ttlStrategy.For<TResult>(), cacheKeyStrategy, onCacheGet, onCacheMiss,
             onCachePut, onCacheGetError, onCachePutError);
 
@@ -798,8 +762,6 @@ public static CachePolicy<TResult> Cache<TResult>(
     /// <exception cref="ArgumentNullException">onCacheGet</exception>
     /// <exception cref="ArgumentNullException">onCacheMiss</exception>
     /// <exception cref="ArgumentNullException">onCachePut</exception>
-    /// <exception cref="ArgumentNullException">onCacheGetError</exception>
-    /// <exception cref="ArgumentNullException">onCachePutError</exception>
     public static CachePolicy<TResult> Cache<TResult>(
         ISyncCacheProvider<TResult> cacheProvider,
         ITtlStrategy<TResult> ttlStrategy,
@@ -807,8 +769,8 @@ public static CachePolicy<TResult> Cache<TResult>(
         Action<Context, string> onCacheGet,
         Action<Context, string> onCacheMiss,
         Action<Context, string> onCachePut,
-        Action<Context, string, Exception> onCacheGetError,
-        Action<Context, string, Exception> onCachePutError)
+        Action<Context, string, Exception>? onCacheGetError,
+        Action<Context, string, Exception>? onCachePutError)
     {
         if (cacheProvider == null) throw new ArgumentNullException(nameof(cacheProvider));
         if (ttlStrategy == null) throw new ArgumentNullException(nameof(ttlStrategy));
@@ -817,8 +779,6 @@ public static CachePolicy<TResult> Cache<TResult>(
         if (onCacheGet == null) throw new ArgumentNullException(nameof(onCacheGet));
         if (onCacheMiss == null) throw new ArgumentNullException(nameof(onCacheMiss));
         if (onCachePut == null) throw new ArgumentNullException(nameof(onCachePut));
-        if (onCacheGetError == null) throw new ArgumentNullException(nameof(onCacheGetError));
-        if (onCachePutError == null) throw new ArgumentNullException(nameof(onCachePutError));
 
         return new CachePolicy<TResult>(cacheProvider, ttlStrategy, cacheKeyStrategy, onCacheGet, onCacheMiss, onCachePut, onCacheGetError, onCachePutError);
     }