| Local overrides are super useful for testing site speed: • Your local setup is likely different from production (not serving from production domains, not using image resize services, using different HTTP compression...) • You might not be able to run tests on localhost, e.g. if you're an external consultant or working in technical SEO (who often want to give specific recommendations to devs as dev attention is scarce and expensive) There are still some limitations of testing changes in DevTools: • Testing a fresh load is a pain (need to clear OS-level DNS cache, need to clear the connection cache in Chrome, need to clear cookies/service worker) • DevTools throttling doesn't represent server connections accurately (you need to throttle at the OS level for accurate data, which slows down your whole computer and requires admin rights) WebPageTest [1] and my own tool DebugBear [2] now support experiments to make it easy to try out content changes in a controlled lab environment. [1] https://product.webpagetest.org/experiments
[2] https://www.debugbear.com/docs/experiments |