There are many layers to caching, both server-side and client-side, and in this short article I want to touch on client-side, or what’s known as Browser Caching.
Browsers like Chrome, Firefox, Safari, etc., are really awesome in that they have a big focus on speed; loading up a website quickly is probably the reason why you prefer one over the other (note: load times are a whole other conversation!). One of their tricks to accomplish this is to cache resources in browser memory so that they don’t have to go and ask the websites’s server for it.
However, when you’ve made updates to your site, your design, colours, layout, updated a graphic, and other similar things the browser may not know that it needs to re-download that file to get the new version (note: there are tricks to this as well, but the solutions are a little inconsistent). Most browsers do eventually expire their cache and re-download a fresh version, but this issue seems to affect website owners and frequent visitors the most – as that audience is the most likely to have a cached version of many of the files. It’s worth noting the average visitor likely won’t experience a caching issue, so for the most part it’s something you can rest easy on.