Your browser saves small pieces of websites — images, scripts, stylesheets — so pages load faster the next time you visit. That's your cache.
Over time, this stored data can get outdated or bloated, which is what causes slow load times or glitchy, broken-looking pages on sites you've visited before.
Clearing your cache forces the browser to grab a completely fresh copy of everything on the page.
The trade-off: sites may load slightly slower the very first time after clearing, and you might get logged out of a few accounts since some login data lives in the same storage.
Quick fix
Clear your cache when a site looks visibly broken or outdated — not as a daily habit. Most browsers don't need it more than once every few weeks.
That's it — two minutes, and now you actually know what that button does.