The mistake: assuming a fix worked

The mistake: assuming a fix worked

The last trap is the trickiest: you make a change, the lab score in Lighthouse jumps to green, and you celebrate. But field data — real-visitor numbers — updates slowly, over a rolling 28-day window. Your fix may be live and working, yet the official score won't catch up for weeks.

Think of it like planting a seed and checking for fruit the next morning.

How to fix your expectations:
— Confirm the fix in lab data right away (instant feedback).
— Then watch field data in PageSpeed Insights over the following weeks.
— Don't undo a good change just because the field score hasn't moved yet.

Try this: after any fix, write down today's date. Check the field numbers again in about four weeks — that's when the real verdict arrives. Patience pays off here.