Speed affects everything that matters online: bounce rate, conversions, ad viewability and how search engines treat your pages. Google measures real-user experience through Core Web Vitals — Largest Contentful Paint (LCP), Cumulative Layout Shift (CLS) and Interaction to Next Paint (INP).
Speed optimization starts with measurement, not guesswork. I look at field data from real users where available, lab tests for diagnosis and the full request waterfall, then fix root causes in priority order: server response, critical rendering path, images, fonts, third-party scripts and layout stability.