How browser cache works and when to clear it

A browser cache stores reusable copies of files such as images, stylesheets and scripts. The next visit can load those files locally instead of downloading them again. Servers attach cache-control rules that tell the browser how long a response can be reused and when it should be validated.

How it works

Caching improves speed and reduces bandwidth, but it can hide a recent change. If a site looks broken after an update, a hard reload may fetch fresh files. Clearing the entire cache is a bigger step: it removes useful local data and may make the next visit slower.

Practical takeaways

Try a hard reload first. If only one site is affected, clear data for that site rather than wiping every stored file. Do not confuse cache with cookies: cookies hold state such as sessions, while cached files are reusable resources.

Developers use versioned filenames or query strings so a changed stylesheet receives a new URL. That prevents old assets from being used after deployment.

In short: Cache is a performance feature, not a fault. Clear it selectively and understand whether the problem is an old asset, a cookie or the server itself.