guessing it would probably be better to put the browser's cache on a normal (mechanical) hard drive

I'm guessing ssd's might wear out more quickly when the same space is rewritten to over and over?

guessing its probably overkill to use ssd for a desktop if its only used for browsing - and if you one of those rare lucky people with lots of spare ram you could maybe use ram for caches/tmp/etc to speed it up