diff --git a/.github/workflows/test-old-branches.yml b/.github/workflows/test-old-branches.yml
index 31b706d740..03cd79f4a2 100644
--- a/.github/workflows/test-old-branches.yml
+++ b/.github/workflows/test-old-branches.yml
@@ -1,9 +1,17 @@
 name: Test old branches
 
 on:
-  # Once weekly On Mondays at 00:00 UTC.
+  # Verify the workflow is successful when this file is updated.
+  push:
+    branches:
+      - master
+      - trunk
+    paths:
+      - '.github/workflows/test-old-branches.yml'
+  # Run twice a month on the 1st and 15th at 00:00 UTC.
   schedule:
-    - cron: '0 0 1,15 * *'
+    - cron: '0 0 1 * *'
+    - cron: '0 0 15 * *'
 
 jobs:
   dispatch-workflows-for-old-branches:
@@ -45,9 +53,11 @@ jobs:
           - branch: '3.7'
             workflow: 'javascript-tests.yml'
 
+    # Run all branches monthly, but only the currently supported one twice per month.
     steps:
       - name: Dispatch workflow run
         uses: actions/github-script@47f7cf65b5ced0830a325f705cad64f2f58dddf7 # v3.1.0
+        if: ${{ github.event_name == 'push' || github.event.schedule == '0 0 15 * *' || matrix.branch == '5.7' }}
         with:
           github-token: ${{ secrets.GHA_OLD_BRANCH_DISPATCH }}
           script: |