I have measured thousands of small-business websites - in my audits the median time to render the main content comes out at over 6 seconds, while Google treats 2.5 seconds as a good result. This is not an abstraction: after about three seconds of waiting, a large share of visitors goes back to the search results and clicks a competitor. The good news is that the causes of slow websites are boringly repetitive. Across hundreds of audits I keep seeing the same seven culprits.
How to measure it at all
Not by eye, and not on the office wi-fi where your browser has the site cached. A reliable measurement comes from PageSpeed Insights - it simulates an average phone on an average connection and reports, among other things, LCP: the time until the largest element of the page appears. You can run the same measurement, through the same Google API, on my home page in half a minute. Look at the mobile score, not desktop - Google ranks sites by their mobile version, and that is how most customers search too.
The seven causes, one by one
- Uncompressed images - cause number one, responsible for most of the megabytes in my measurements. A phone photo weighs 4-8 MB; on a website it should weigh 50-200 KB in WebP or AVIF. Ten such photos are the difference between a 0.5 MB page and a 40 MB one.
- Cheap shared hosting - a server that answers after two seconds loses the race before the browser downloads anything. A server response time (TTFB) above 0.8 s is the tell.
- Too many WordPress plugins - each adds its own scripts and styles, often loaded on every page while needed on one. Above 20 active plugins I rarely see a site that clears Google's threshold.
- A heavy "all-purpose" theme - do-everything themes drag in three slider libraries and a full icon set regardless of what you use. That is 1-3 MB of baggage before the first photo loads.
- Third-party scripts - chats, maps, ad pixels, review widgets. Each one is a separate connection to a foreign server your page waits for. Three such widgets can double the load time.
- No caching - without a cache the server builds the page from scratch on every visit. A cache plugin is the cheapest WordPress speed-up there is, yet half the sites in my audits run without one.
- Outdated PHP and database versions - WordPress on a years-old PHP runs up to half as fast as on a current one. Switching is often one click in the hosting panel that nobody told the owner about.
What to fix first
Order matters, because the first two items usually deliver most of the gain: first images (compression and a modern format), then caching, then cutting plugins and scripts, and hosting last, if TTFB still exceeds 0.8 s. Measure after every change - otherwise you cannot tell what worked. That is also how my speed-up service for existing sites runs: a measurement before, the fix, a measurement after - and the result is what the invoice is based on.
What not to do
Do not start by moving to pricier hosting "because it is slow" - if the site hauls 15 MB of images, a faster server helps cosmetically. Do not install three optimisation plugins at once; they can undo each other's work and break the site on updates. And do not buy "SEO optimisation" before the site gets under the speed threshold - ranking a slow site is hauling anchor with the brake on. If the site is over five years old and carries half of this list, honestly compare the cost of fixing with the cost of a new one - here I describe how to choose the technology, and rough prices are in the honest price guide.