Your Repeat Visitors Are Downloading Everything. Again.
Every. Single. Visit.
Same CSS. Same JavaScript. Same logo. Same fonts. All downloaded fresh like they have never been to your site before.
That is what happens without proper browser caching. And it is killing your Core Web Vitals.
What Browser Caching Does
It tells the browser: "Hey, you already downloaded this file. It has not changed. Use the copy you have."
The visitor's second page load (and every subsequent one) is dramatically faster. We are talking 50-80% faster in many cases.
How to Set It Up
Set `Cache-Control` headers on your static assets. Images, CSS, JavaScript, fonts — all of it.
For assets with hashed filenames (like `app.a1b2c3.js`), set `max-age=31536000` (one year). The hash changes when the file changes, so stale cache is never a problem.
For HTML pages, use shorter cache times or `no-cache` with ETags. You want fresh content but cached assets.
The Common Mistake
Setting cache headers on HTML pages with long max-age values. Now your users see stale content and you cannot push updates. Whoops.
Cache assets aggressively. Cache HTML cautiously. Pair this with a CDN and you have got a serious speed stack. Google's SEO starter guide emphasizes the importance of fast-loading pages.
This is one of many speed tasks in our 113-point SEO checklist. Free to use. No credit card needed. Set up in 30 seconds.