diff --git a/docs/reference/functions/AuthCheck.md b/docs/reference/functions/AuthCheck.md
index 06738074..dfb0e3ea 100644
--- a/docs/reference/functions/AuthCheck.md
+++ b/docs/reference/functions/AuthCheck.md
@@ -8,7 +8,7 @@
 
 > **AuthCheck**(`__namedParameters`): `ReactElement`
 
-Defined in: [src/auth.tsx:257](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L257)
+Defined in: [src/auth.tsx:259](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L259)
 
 ## Parameters
 
diff --git a/docs/reference/functions/ClaimsCheck.md b/docs/reference/functions/ClaimsCheck.md
index 5138d974..fa5ca95e 100644
--- a/docs/reference/functions/ClaimsCheck.md
+++ b/docs/reference/functions/ClaimsCheck.md
@@ -8,7 +8,7 @@
 
 > **ClaimsCheck**(`__namedParameters`): `Element`
 
-Defined in: [src/auth.tsx:213](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L213)
+Defined in: [src/auth.tsx:215](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L215)
 
 ## Parameters
 
diff --git a/docs/reference/functions/StorageImage.md b/docs/reference/functions/StorageImage.md
index 24370e02..59c9a60b 100644
--- a/docs/reference/functions/StorageImage.md
+++ b/docs/reference/functions/StorageImage.md
@@ -8,7 +8,7 @@
 
 > **StorageImage**(`props`): `Element`
 
-Defined in: [src/storage.tsx:78](https://github.com/FirebaseExtended/reactfire/blob/main/src/storage.tsx#L78)
+Defined in: [src/storage.tsx:82](https://github.com/FirebaseExtended/reactfire/blob/main/src/storage.tsx#L82)
 
 ## Parameters
 
diff --git a/docs/reference/functions/useCallableFunctionResponse.md b/docs/reference/functions/useCallableFunctionResponse.md
index ddd4987c..3ea2b8d8 100644
--- a/docs/reference/functions/useCallableFunctionResponse.md
+++ b/docs/reference/functions/useCallableFunctionResponse.md
@@ -8,7 +8,7 @@
 
 > **useCallableFunctionResponse**\<`RequestData`, `ResponseData`\>(`functionName`, `options?`): [`ObservableStatus`](../interfaces/ObservableStatus.md)\<`ResponseData`\>
 
-Defined in: [src/functions.tsx:13](https://github.com/FirebaseExtended/reactfire/blob/main/src/functions.tsx#L13)
+Defined in: [src/functions.tsx:14](https://github.com/FirebaseExtended/reactfire/blob/main/src/functions.tsx#L14)
 
 Calls a callable function.
 
diff --git a/docs/reference/functions/useSigninCheck.md b/docs/reference/functions/useSigninCheck.md
index 32e3e619..895405bc 100644
--- a/docs/reference/functions/useSigninCheck.md
+++ b/docs/reference/functions/useSigninCheck.md
@@ -8,7 +8,7 @@
 
 > **useSigninCheck**(`options?`): [`ObservableStatus`](../interfaces/ObservableStatus.md)\<[`SigninCheckResult`](../type-aliases/SigninCheckResult.md)\>
 
-Defined in: [src/auth.tsx:134](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L134)
+Defined in: [src/auth.tsx:136](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L136)
 
 Subscribe to the signed-in status of a user.
 
diff --git a/docs/reference/functions/useStorageDownloadURL.md b/docs/reference/functions/useStorageDownloadURL.md
index 898c4931..ced03bbf 100644
--- a/docs/reference/functions/useStorageDownloadURL.md
+++ b/docs/reference/functions/useStorageDownloadURL.md
@@ -8,7 +8,7 @@
 
 > **useStorageDownloadURL**\<`T`\>(`ref`, `options?`): [`ObservableStatus`](../interfaces/ObservableStatus.md)\<`string` \| `T`\>
 
-Defined in: [src/storage.tsx:29](https://github.com/FirebaseExtended/reactfire/blob/main/src/storage.tsx#L29)
+Defined in: [src/storage.tsx:30](https://github.com/FirebaseExtended/reactfire/blob/main/src/storage.tsx#L30)
 
 Subscribe to a storage ref's download URL
 
diff --git a/docs/reference/functions/useStorageTask.md b/docs/reference/functions/useStorageTask.md
index ccda3ddf..f6cbc13d 100644
--- a/docs/reference/functions/useStorageTask.md
+++ b/docs/reference/functions/useStorageTask.md
@@ -8,7 +8,7 @@
 
 > **useStorageTask**\<`T`\>(`task`, `ref`, `options?`): [`ObservableStatus`](../interfaces/ObservableStatus.md)\<`T` \| `UploadTaskSnapshot`\>
 
-Defined in: [src/storage.tsx:16](https://github.com/FirebaseExtended/reactfire/blob/main/src/storage.tsx#L16)
+Defined in: [src/storage.tsx:17](https://github.com/FirebaseExtended/reactfire/blob/main/src/storage.tsx#L17)
 
 Subscribe to the progress of a storage task
 
diff --git a/docs/reference/interfaces/AuthCheckProps.md b/docs/reference/interfaces/AuthCheckProps.md
index 37e7b895..c5edcb62 100644
--- a/docs/reference/interfaces/AuthCheckProps.md
+++ b/docs/reference/interfaces/AuthCheckProps.md
@@ -6,7 +6,7 @@
 
 # Interface: AuthCheckProps
 
-Defined in: [src/auth.tsx:52](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L52)
+Defined in: [src/auth.tsx:54](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L54)
 
 ## Properties
 
@@ -14,7 +14,7 @@ Defined in: [src/auth.tsx:52](https://github.com/FirebaseExtended/reactfire/blob
 
 > **children**: `ReactNode`
 
-Defined in: [src/auth.tsx:54](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L54)
+Defined in: [src/auth.tsx:56](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L56)
 
 ***
 
@@ -22,7 +22,7 @@ Defined in: [src/auth.tsx:54](https://github.com/FirebaseExtended/reactfire/blob
 
 > **fallback**: `ReactNode`
 
-Defined in: [src/auth.tsx:53](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L53)
+Defined in: [src/auth.tsx:55](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L55)
 
 ***
 
@@ -30,4 +30,4 @@ Defined in: [src/auth.tsx:53](https://github.com/FirebaseExtended/reactfire/blob
 
 > `optional` **requiredClaims?**: `Object`
 
-Defined in: [src/auth.tsx:55](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L55)
+Defined in: [src/auth.tsx:57](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L57)
diff --git a/docs/reference/interfaces/ClaimCheckErrors.md b/docs/reference/interfaces/ClaimCheckErrors.md
index 470ca5ab..ce0afa98 100644
--- a/docs/reference/interfaces/ClaimCheckErrors.md
+++ b/docs/reference/interfaces/ClaimCheckErrors.md
@@ -6,7 +6,7 @@
 
 # Interface: ClaimCheckErrors
 
-Defined in: [src/auth.tsx:65](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L65)
+Defined in: [src/auth.tsx:67](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L67)
 
 ## Indexable
 
diff --git a/docs/reference/interfaces/ClaimsCheckProps.md b/docs/reference/interfaces/ClaimsCheckProps.md
index 4d39e79b..34375923 100644
--- a/docs/reference/interfaces/ClaimsCheckProps.md
+++ b/docs/reference/interfaces/ClaimsCheckProps.md
@@ -6,7 +6,7 @@
 
 # Interface: ClaimsCheckProps
 
-Defined in: [src/auth.tsx:58](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L58)
+Defined in: [src/auth.tsx:60](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L60)
 
 ## Properties
 
@@ -14,7 +14,7 @@ Defined in: [src/auth.tsx:58](https://github.com/FirebaseExtended/reactfire/blob
 
 > **children**: `ReactNode`
 
-Defined in: [src/auth.tsx:61](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L61)
+Defined in: [src/auth.tsx:63](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L63)
 
 ***
 
@@ -22,7 +22,7 @@ Defined in: [src/auth.tsx:61](https://github.com/FirebaseExtended/reactfire/blob
 
 > **fallback**: `ReactNode`
 
-Defined in: [src/auth.tsx:60](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L60)
+Defined in: [src/auth.tsx:62](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L62)
 
 ***
 
@@ -30,7 +30,7 @@ Defined in: [src/auth.tsx:60](https://github.com/FirebaseExtended/reactfire/blob
 
 > **requiredClaims**: `object`
 
-Defined in: [src/auth.tsx:62](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L62)
+Defined in: [src/auth.tsx:64](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L64)
 
 #### Index Signature
 
@@ -42,4 +42,4 @@ Defined in: [src/auth.tsx:62](https://github.com/FirebaseExtended/reactfire/blob
 
 > **user**: `User`
 
-Defined in: [src/auth.tsx:59](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L59)
+Defined in: [src/auth.tsx:61](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L61)
diff --git a/docs/reference/interfaces/ClaimsValidator.md b/docs/reference/interfaces/ClaimsValidator.md
index feb558fd..436ddd45 100644
--- a/docs/reference/interfaces/ClaimsValidator.md
+++ b/docs/reference/interfaces/ClaimsValidator.md
@@ -6,11 +6,11 @@
 
 # Interface: ClaimsValidator()
 
-Defined in: [src/auth.tsx:91](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L91)
+Defined in: [src/auth.tsx:93](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L93)
 
 > **ClaimsValidator**(`claims`): `object`
 
-Defined in: [src/auth.tsx:92](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L92)
+Defined in: [src/auth.tsx:94](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L94)
 
 ## Parameters
 
diff --git a/docs/reference/interfaces/SignInCheckOptionsBasic.md b/docs/reference/interfaces/SignInCheckOptionsBasic.md
index 6c9f2d66..66967bf8 100644
--- a/docs/reference/interfaces/SignInCheckOptionsBasic.md
+++ b/docs/reference/interfaces/SignInCheckOptionsBasic.md
@@ -6,7 +6,7 @@
 
 # Interface: SignInCheckOptionsBasic
 
-Defined in: [src/auth.tsx:83](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L83)
+Defined in: [src/auth.tsx:85](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L85)
 
 ## Extends
 
@@ -23,7 +23,7 @@ Defined in: [src/auth.tsx:83](https://github.com/FirebaseExtended/reactfire/blob
 
 > `optional` **forceRefresh?**: `boolean`
 
-Defined in: [src/auth.tsx:84](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L84)
+Defined in: [src/auth.tsx:86](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L86)
 
 ***
 
diff --git a/docs/reference/interfaces/SignInCheckOptionsClaimsObject.md b/docs/reference/interfaces/SignInCheckOptionsClaimsObject.md
index 092cde82..09a1eae0 100644
--- a/docs/reference/interfaces/SignInCheckOptionsClaimsObject.md
+++ b/docs/reference/interfaces/SignInCheckOptionsClaimsObject.md
@@ -6,7 +6,7 @@
 
 # Interface: SignInCheckOptionsClaimsObject
 
-Defined in: [src/auth.tsx:87](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L87)
+Defined in: [src/auth.tsx:89](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L89)
 
 ## Extends
 
@@ -18,7 +18,7 @@ Defined in: [src/auth.tsx:87](https://github.com/FirebaseExtended/reactfire/blob
 
 > `optional` **forceRefresh?**: `boolean`
 
-Defined in: [src/auth.tsx:84](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L84)
+Defined in: [src/auth.tsx:86](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L86)
 
 #### Inherited from
 
@@ -54,7 +54,7 @@ Defined in: [src/index.ts:26](https://github.com/FirebaseExtended/reactfire/blob
 
 > **requiredClaims**: `ParsedToken`
 
-Defined in: [src/auth.tsx:88](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L88)
+Defined in: [src/auth.tsx:90](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L90)
 
 ***
 
diff --git a/docs/reference/interfaces/SignInCheckOptionsClaimsValidator.md b/docs/reference/interfaces/SignInCheckOptionsClaimsValidator.md
index 83517d7a..5ba7f609 100644
--- a/docs/reference/interfaces/SignInCheckOptionsClaimsValidator.md
+++ b/docs/reference/interfaces/SignInCheckOptionsClaimsValidator.md
@@ -6,7 +6,7 @@
 
 # Interface: SignInCheckOptionsClaimsValidator
 
-Defined in: [src/auth.tsx:98](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L98)
+Defined in: [src/auth.tsx:100](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L100)
 
 ## Extends
 
@@ -18,7 +18,7 @@ Defined in: [src/auth.tsx:98](https://github.com/FirebaseExtended/reactfire/blob
 
 > `optional` **forceRefresh?**: `boolean`
 
-Defined in: [src/auth.tsx:84](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L84)
+Defined in: [src/auth.tsx:86](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L86)
 
 #### Inherited from
 
@@ -82,4 +82,4 @@ Defined in: [src/index.ts:31](https://github.com/FirebaseExtended/reactfire/blob
 
 > **validateCustomClaims**: [`ClaimsValidator`](ClaimsValidator.md)
 
-Defined in: [src/auth.tsx:99](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L99)
+Defined in: [src/auth.tsx:101](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L101)
diff --git a/docs/reference/type-aliases/SigninCheckResult.md b/docs/reference/type-aliases/SigninCheckResult.md
index bb80be74..f6f71bd1 100644
--- a/docs/reference/type-aliases/SigninCheckResult.md
+++ b/docs/reference/type-aliases/SigninCheckResult.md
@@ -8,4 +8,4 @@
 
 > **SigninCheckResult** = \{ `errors`: \{ \}; `hasRequiredClaims`: `false`; `signedIn`: `false`; `user`: `null`; \} \| \{ `errors`: [`ClaimCheckErrors`](../interfaces/ClaimCheckErrors.md); `hasRequiredClaims`: `boolean`; `signedIn`: `true`; `user`: `User`; \}
 
-Defined in: [src/auth.tsx:69](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L69)
+Defined in: [src/auth.tsx:71](https://github.com/FirebaseExtended/reactfire/blob/main/src/auth.tsx#L71)
diff --git a/docs/reference/type-aliases/StorageImageProps.md b/docs/reference/type-aliases/StorageImageProps.md
index b75fa337..f4dcf98f 100644
--- a/docs/reference/type-aliases/StorageImageProps.md
+++ b/docs/reference/type-aliases/StorageImageProps.md
@@ -8,7 +8,7 @@
 
 > **StorageImageProps** = `object`
 
-Defined in: [src/storage.tsx:36](https://github.com/FirebaseExtended/reactfire/blob/main/src/storage.tsx#L36)
+Defined in: [src/storage.tsx:40](https://github.com/FirebaseExtended/reactfire/blob/main/src/storage.tsx#L40)
 
 ## Properties
 
@@ -16,7 +16,7 @@ Defined in: [src/storage.tsx:36](https://github.com/FirebaseExtended/reactfire/b
 
 > `optional` **placeHolder?**: `React.ReactNode`
 
-Defined in: [src/storage.tsx:40](https://github.com/FirebaseExtended/reactfire/blob/main/src/storage.tsx#L40)
+Defined in: [src/storage.tsx:44](https://github.com/FirebaseExtended/reactfire/blob/main/src/storage.tsx#L44)
 
 ***
 
@@ -24,7 +24,7 @@ Defined in: [src/storage.tsx:40](https://github.com/FirebaseExtended/reactfire/b
 
 > `optional` **storage?**: `FirebaseStorage`
 
-Defined in: [src/storage.tsx:38](https://github.com/FirebaseExtended/reactfire/blob/main/src/storage.tsx#L38)
+Defined in: [src/storage.tsx:42](https://github.com/FirebaseExtended/reactfire/blob/main/src/storage.tsx#L42)
 
 ***
 
@@ -32,7 +32,7 @@ Defined in: [src/storage.tsx:38](https://github.com/FirebaseExtended/reactfire/b
 
 > **storagePath**: `string`
 
-Defined in: [src/storage.tsx:37](https://github.com/FirebaseExtended/reactfire/blob/main/src/storage.tsx#L37)
+Defined in: [src/storage.tsx:41](https://github.com/FirebaseExtended/reactfire/blob/main/src/storage.tsx#L41)
 
 ***
 
@@ -40,4 +40,4 @@ Defined in: [src/storage.tsx:37](https://github.com/FirebaseExtended/reactfire/b
 
 > `optional` **suspense?**: `boolean`
 
-Defined in: [src/storage.tsx:39](https://github.com/FirebaseExtended/reactfire/blob/main/src/storage.tsx#L39)
+Defined in: [src/storage.tsx:43](https://github.com/FirebaseExtended/reactfire/blob/main/src/storage.tsx#L43)
diff --git a/src/auth.tsx b/src/auth.tsx
index 1bebf526..9fba1a46 100644
--- a/src/auth.tsx
+++ b/src/auth.tsx
@@ -1,7 +1,7 @@
 import * as React from 'react';
 import { user } from 'rxfire/auth';
 import { preloadObservable, ReactFireOptions, useAuth, useObservable, ObservableStatus, ReactFireError } from './';
-import { from, of } from 'rxjs';
+import { from, of, defer } from 'rxjs';
 import { map, switchMap } from 'rxjs/operators';
 import { useSuspenseEnabledFromConfigAndContext } from './firebaseApp';
 
@@ -44,7 +44,9 @@ export function useIdTokenResult(user: User, forceRefresh = false, options?: Rea
   }
 
   const observableId = `auth:idTokenResult:${user.uid}:forceRefresh=${forceRefresh}`;
-  const observable$ = from(user.getIdTokenResult(forceRefresh));
+  // Wrap in `defer` so the token fetch runs lazily on subscription rather than
+  // eagerly on every render.
+  const observable$ = defer(() => from(user.getIdTokenResult(forceRefresh)));
 
   return useObservable(observableId, observable$, options);
 }
diff --git a/src/functions.tsx b/src/functions.tsx
index 501822b1..e9f1f34b 100644
--- a/src/functions.tsx
+++ b/src/functions.tsx
@@ -1,4 +1,5 @@
 import { httpsCallable as rxHttpsCallable } from 'rxfire/functions';
+import { defer } from 'rxjs';
 import { ReactFireOptions, useObservable, ObservableStatus } from './';
 import { useFunctions } from '.';
 
@@ -20,7 +21,9 @@ export function useCallableFunctionResponse<RequestData, ResponseData>(
   const functions = useFunctions();
   const observableId = `functions:callableResponse:${functionName}:${JSON.stringify(options?.data)}:${JSON.stringify(options?.httpsCallableOptions)}`;
   const obsFactory = rxHttpsCallable<RequestData, ResponseData>(functions, functionName, options?.httpsCallableOptions);
-  const observable$ = obsFactory(options?.data);
+  // Wrap in `defer` so the function is invoked lazily on subscription rather than
+  // on every render (each render otherwise calls the cloud function and discards it).
+  const observable$ = defer(() => obsFactory(options?.data));
 
   return useObservable(observableId, observable$, options);
 }
diff --git a/src/storage.tsx b/src/storage.tsx
index 5a0299da..92f27a51 100644
--- a/src/storage.tsx
+++ b/src/storage.tsx
@@ -1,5 +1,6 @@
 import * as React from 'react';
 import { getDownloadURL, fromTask } from 'rxfire/storage';
+import { defer } from 'rxjs';
 import { ReactFireOptions, useObservable, ObservableStatus, useStorage } from './';
 import { useSuspenseEnabledFromConfigAndContext } from './firebaseApp';
 import { ref } from 'firebase/storage';
@@ -28,7 +29,10 @@ export function useStorageTask<T = unknown>(task: UploadTask, ref: StorageRefere
  */
 export function useStorageDownloadURL<T = string>(ref: StorageReference, options?: ReactFireOptions<T>): ObservableStatus<string | T> {
   const observableId = `storage:downloadUrl:${ref.toString()}`;
-  const observable$ = getDownloadURL(ref);
+  // Wrap in `defer` so the download URL request is created lazily on subscription
+  // rather than eagerly on every render (which fires a discarded request each time,
+  // and an unhandled rejection when the object is missing).
+  const observable$ = defer(() => getDownloadURL(ref));
 
   return useObservable(observableId, observable$, options);
 }
diff --git a/test/auth.test.tsx b/test/auth.test.tsx
index 3a66784f..647ef683 100644
--- a/test/auth.test.tsx
+++ b/test/auth.test.tsx
@@ -9,6 +9,7 @@ import {
   AuthProvider,
   useUser,
   useSigninCheck,
+  useIdTokenResult,
   ClaimCheckErrors,
   ClaimsValidator,
 } from '../src/index';
@@ -16,7 +17,7 @@ import { baseConfig } from './appConfig';
 import { FirebaseApp, initializeApp } from 'firebase/app';
 import { randomString } from './test-utils';
 
-import { getAuth, GoogleAuthProvider, signInWithCredential, signInWithCustomToken, signOut, connectAuthEmulator, UserCredential } from 'firebase/auth';
+import { getAuth, GoogleAuthProvider, signInWithCredential, signInWithCustomToken, signOut, connectAuthEmulator, UserCredential, User } from 'firebase/auth';
 
 describe('Authentication', () => {
   let app: FirebaseApp;
@@ -388,4 +389,22 @@ describe('Authentication', () => {
       await findByTestId('signed-out');
     });
   });
+
+  describe('useIdTokenResult', () => {
+    it('defers the token fetch so it does not re-run on every render', async () => {
+      const getIdTokenResult = vi.fn().mockResolvedValue({ claims: {} });
+      const fakeUser = { uid: randomString(), getIdTokenResult } as unknown as User;
+
+      const { result, rerender } = renderHook(() => useIdTokenResult(fakeUser, false));
+
+      await waitFor(() => expect(result.current.status).toEqual('success'));
+
+      // The request is created lazily inside `defer` and useObservable subscribes
+      // once, so re-rendering must not trigger additional token fetches.
+      rerender();
+      rerender();
+
+      expect(getIdTokenResult).toHaveBeenCalledTimes(1);
+    });
+  });
 });
diff --git a/test/functions.test.tsx b/test/functions.test.tsx
index 10ef5a23..41f4b288 100644
--- a/test/functions.test.tsx
+++ b/test/functions.test.tsx
@@ -7,6 +7,17 @@ import { renderHook, waitFor } from '@testing-library/react';
 import { randomString } from './test-utils';
 import * as React from 'react';
 
+// `functions.tsx` calls `httpsCallable` (via rxfire) to create the callable used inside
+// `defer`. Wrapping it in `vi.fn` (calling through to the real implementation by default)
+// lets the regression test below count invocations without touching the emulator.
+vi.mock('firebase/functions', async (importOriginal) => {
+  const actual = await importOriginal<typeof import('firebase/functions')>();
+  return {
+    ...actual,
+    httpsCallable: vi.fn(actual.httpsCallable),
+  };
+});
+
 describe('Functions', () => {
   const app = initializeApp(baseConfig);
   const functions = getFunctions(app);
@@ -46,5 +57,35 @@ describe('Functions', () => {
       await waitFor(() => expect(result.current.status).toEqual('success'));
       expect(result.current.data).toEqual(testText.toUpperCase());
     });
+
+    it('defers the function call so it does not re-invoke on every render', async () => {
+      const testText = randomString();
+      const mockedHttpsCallable = vi.mocked(httpsCallable);
+      const originalImpl = mockedHttpsCallable.getMockImplementation()! as typeof httpsCallable;
+
+      // Wrap the real callable so we can count invocations of the cloud function
+      // itself, not just how many times `httpsCallable` is called to create it.
+      const realCallable = originalImpl<{ text: string }, string>(functions, 'capitalizeText');
+      const callSpy = vi.fn((data?: { text: string } | null) => realCallable(data));
+      mockedHttpsCallable.mockImplementation(() => callSpy as unknown as ReturnType<typeof httpsCallable>);
+
+      try {
+        const { result, rerender } = renderHook(
+          () => useCallableFunctionResponse<{ text: string }, string>('capitalizeText', { data: { text: testText } }),
+          { wrapper: Provider }
+        );
+
+        await waitFor(() => expect(result.current.status).toEqual('success'));
+
+        // The request is created lazily inside `defer` and useObservable subscribes
+        // once, so re-rendering must not trigger additional cloud function calls.
+        rerender();
+        rerender();
+
+        expect(callSpy).toHaveBeenCalledTimes(1);
+      } finally {
+        mockedHttpsCallable.mockImplementation(originalImpl);
+      }
+    });
   });
 });