Every few months a business owner shows us a red performance score and asks if their site is broken. Sometimes it is. Just as often, the score is measuring the wrong thing — and the fixes their previous agency sold them moved a lab number without moving a single customer.
Core Web Vitals are Google’s three user-experience measurements: how fast the main content appears (LCP), how quickly the page responds when you tap or type (INP, which replaced the old FID metric), and how much the layout jumps around while loading (CLS). They influence rankings, but more importantly they describe what your customers actually feel.
Field data beats lab data
The score from a testing tool is a lab simulation — one synthetic device, one synthetic connection. What Google actually uses is field data: measurements collected from real visitors to your site over the previous 28 days.
The two routinely disagree. A site can score 95 in the lab and still fail in the field because real customers are on three-year-old phones in a parking lot. Experienced owners check the field data first and treat lab runs as a debugging tool, not a report card.
The mistakes we see most
The same handful of problems shows up on almost every slow local-business site:
- A full-screen hero video or oversized hero image that delays the largest paint by seconds.
- Images uploaded straight from a phone — 4,000 pixels wide, serving a 400-pixel slot.
- Web fonts loading late and swapping mid-read, shoving the layout around (CLS).
- A drawer of third-party scripts — chat, pixels, maps, pop-ups — each “only” a hundred milliseconds.
- Booking or menu widgets embedded as heavy iframes on the most-visited page.
Where the wins are
The good news: local-business sites are usually small enough that a focused pass fixes most of it. Size and compress images to the slot they fill and serve modern formats. Load the one hero asset eagerly and lazy-load everything below the fold. Preload the one or two fonts you actually use and reserve space so nothing shifts. Audit the third-party scripts yearly and delete the ones nobody can name a reason for.
None of this is a stunt, and that’s the point. Vitals reward sites that are simply built with care — which is also exactly what customers reward.