Speed is a conversion problem, not a vanity metric
Visitors judge a business by how fast its site responds. When pages load slowly or shift while loading, people lose trust and leave before they ever see an offer. Core Web Vitals put numbers on that experience, which makes it possible to treat speed as a measurable revenue lever rather than a guess.
Know the three metrics that matter
Largest Contentful Paint measures how quickly the main content appears, Interaction to Next Paint measures how fast the page responds to input, and Cumulative Layout Shift measures how much the layout jumps around while loading. Each maps to a real frustration: waiting, lag, and misclicks. Tracking all three gives a complete picture of perceived speed.
Fix the heavy hitters first
Most sites improve fastest by compressing and right-sizing images, deferring non-critical scripts, caching aggressively, and reserving space for media so the layout stays stable. These changes often move the metrics more than a full rebuild, and they rarely require touching core business logic.
Measure in the field, not just the lab
Lab tools are useful for debugging, but real users on real devices and networks tell the truth. Field data from actual visitors shows which pages hurt conversions, so the team can prioritize the fixes that protect the most leads instead of chasing a perfect score.