Patience for a slow-loading website is practically nonexistent. Repeated Google studies show the likelihood of someone abandoning a page rises sharply as loading time moves from two to three, four or five seconds. WPO (Web Performance Optimization) is the work of making sure that never happens.
Why it affects sales so much, not just "how it feels"
It's not just a comfort issue. Every extra second of loading time translates, measurably, into fewer pages viewed, fewer conversions and a higher bounce rate. In ecommerce, the difference between a fast site and a slow one can mean several percentage points of lost sales every month.
The most common causes of a slow website
Unoptimised images, or images far larger than needed. Too many plugins or third-party scripts loading things almost nobody uses. Hosting that's insufficient for the site's actual traffic. And unnecessarily heavy code, piled up over time and never cleaned.
What you can actually do about it
Compress and resize images to the actual size they're displayed at (don't upload a 4000-pixel file to show it at 400). Enable caching so the browser doesn't re-download the same thing on every visit. Lazy-load anything not visible at the top of the page. And when hosting falls short, migrate to one that matches actual traffic.
How to measure it without relying on gut feeling
Free tools like Google's PageSpeed Insights give an objective score and point out exactly what's slowing the site down, instead of having to guess.
Frequently asked questions
What loading time counts as "good"?
As a general benchmark, under 2.5 seconds for the main content is considered a good result under Google's current standards (Core Web Vitals).
Does optimising speed also improve SEO rankings?
Yes, directly: speed is one of the factors Google uses to rank pages, on top of the indirect effect of improving experience and reducing abandonment.
How much can speed improve without rebuilding the whole site?
Quite a lot, in most cases. Optimising images, enabling caching and reviewing plugins usually brings noticeable improvements without touching the design or structure at all.