Use field and lab measurements to identify the page changes that actually improve user experience.
The core idea
Core Web Vitals focus on loading performance, responsiveness, and visual stability. Large images, blocking scripts, layout shifts, and expensive client work can all affect the experience.
A practical way to approach it
Measure before changing code, inspect image dimensions and formats, reserve space for media, reduce unnecessary JavaScript, and defer non-critical resources. Re-test on a representative mobile device and network.
Try it in a small project
Choose a slow page, record its key metrics, optimize its largest image and one render-blocking resource, then compare results. Keep a note of what changed so improvements are attributable.
Common mistakes to avoid
A perfect lab score does not guarantee good field performance. Monitor real users where possible and prioritize changes that improve actual tasks.
Key takeaway
Keep the first version small, make your assumptions explicit, and verify the result with a repeatable test. For production use, check the current official documentation for the tools and versions you choose.