Page Speed

Page speed is how fast your page loads and becomes usable. It matters twice: search engines use aspects of it as a ranking signal, and users abandon slow pages regardless of ranking. Two kinds of measurement exist and they answer different questions — lab data (a synthetic test such as Lighthouse, run in controlled conditions) and field data (what real visitors actually experienced, which is what Core Web Vitals reports).

Optimise against field data and use lab tools to diagnose. The wins are unglamorous and repeatable: compress and correctly size images, serve modern formats, defer non-critical JavaScript, remove unused third-party scripts, set proper caching, and put a CDN in front. Third-party tags are the most common culprit on marketing sites — a single chat widget or testing script can cost more than every image on the page. And measure on a mid-range mobile device over a throttled connection, not on your laptop.

Speed is a business argument before it is a technical one, and it fails when SEO owns it alone. The realistic senior job is converting milliseconds into money — tie load time to conversion rate and revenue, then take that number to whoever controls the tag manager and the marketing stack, because the biggest regressions are almost always someone else’s script. Set a performance budget, monitor for regressions after every release, and pick your battles: four seconds to two is transformative, 92 to 98 on a lab score is usually vanity. Past a threshold, speed stops being a ranking lever and becomes purely a conversion one.