The behaviour of service workers can be confusing to start with because they keep running in the background, so refreshing the page might not always do what you expect. As a result, as you start out we’d suggest including frequent console logging in your code to help follow what’s happening. Additionally, Chrome Developer Tools can provide detailed insight into the service workers on a page. In Developer Tools, navigate to the Application tab and you’ll see a Service Workers tab. It’s particularly worth noting that you can manually update and unregister service workers on this page, which is helpful when developing to ensure you pick up the latest changes. Additionally, the Clear Storage tab will enable you to purge cached resources, which can also come in very useful. Once you have Workbox up and running and handling your caching, you’ll also find that it provides its own very rich console messages which are certainly worth keeping an eye on.