Slowness costs you twice: a visitor who leaves before seeing the product, and a lower position in search results.
Cause one: images
A four-megabyte image uploaded straight from the camera is the single most common cause. Export at actual display size, use modern formats, and never upload an image larger than the space it will occupy.
Cause two: accumulated apps
Every installed app adds code loaded on every page, including apps you no longer use. Review your app list and remove what you genuinely do not use — the fastest improvement available.
Cause three: tracking scripts
Three pixels, two analytics tools and a chat script combine to delay first content. Keep what you actually use for decisions and remove the rest.
Measure on a real device
Test from a phone on an ordinary connection, not from your desktop on fast Wi-Fi. The gap is wide, and the customer's real experience is closer to the former.
Three numbers are enough
- When the largest element on the page becomes visible.
- Whether the layout shifts while loading — a common cause of mis-taps.
- How long the page takes to respond to the first interaction.
Start with the pages that matter
Optimise the homepage and your most-visited product page first. Those two carry most of your traffic, and improving them shows in the numbers immediately.