Website speed isn't a technical detail for developers. It's one of the few factors that affect conversions directly and measurably – and at the same time one of the most neglected.
What the data says
Google has long reported that when load time rises from one to three seconds, the probability of leaving goes up by a third. We see similar numbers in our own projects: after an e-shop redesign where LCP improved from seven seconds to 0.8 seconds, completed orders grew by a third with no change in advertising.
How we measure speed
We use Lighthouse in mobile mode and Core Web Vitals from real visits. We watch three numbers: LCP (when the main content appears), CLS (whether content jumps) and INP (how fast the site reacts to a click). The target on every project: LCP under one second, CLS under 0.05 and INP under 200 ms. We measure at handover and then every month as part of care.
What slows a website down
Most often unoptimised images, dozens of third-party scripts (chats, analytics, widgets) and templates that load everything at once. The second culprit is fonts: five font weights from an external server can delay text by a second.
What we do about it
We serve images in AVIF and WebP at the size the device needs. Third-party scripts load only after interaction, or not at all. We host fonts ourselves and use one or two weights. Animations and WebGL load only after the first render of content, so they never block text.
What you can do today
Open your website on a phone with wifi off and count. If the main content appears after more than two seconds, you're losing customers before they read the first sentence. We do a speed audit as part of the free intro call.