I always try to keep a clean slate on my Linux box. Not only when it comes to security but one thing I really hate is the massive amount of stuff that gets downloaded as “chemical waste by-products” like a gazilion revisions of twitter and other (anti-)social media icons, pictures, style-sheets etc. etc. etc.
Obviously you can set limitations to the size of the cache but to prevent this pollution from being retained across reboots and clogging up the inode tables with useless entries.