Any time I’ve worked with performance tuning, I’ve found that caching gives the highest rewards with the least work. It’s entirely possible to see thousand-fold increases if you employ caching in the right places. My WordPress install used to run complex SQL queries on every page, and I benchmarked it at 4 pages/second under ideal conditions. I now do some trivial caching of the results of those queries and can push over 400 pages/second. Your OS caches files in unused memory since it’s so much faster than disk, and your browser caches static assets on a site so your browser doesn’t have to download them again for every page view.

But here’s what I’m actually posting about: What is it with people and cleaning out their caches all the time? It’s like caches are some sort of gunk that builds up and clogs up the works. It’d be like me being distraught to find that money is clogging up my bank account and trying to find a way to purge all the money so I had more room in the bank. This is one of those things that’s slightly amusing and only slightly irritating, until you talk to the tenth user in a row who talks about clearing their caches to try to make their computer faster. Why?! What is going through their heads?