Keeping downloaded Xcode components
Perhaps its a remnant of my dial-up days, but I’m one of those old fashioned people that keeps local copies of all the stuff I download. Saves me having to download them again if I need to reinstall.
In the case of Xcode 4.x, components are downloaded and installed from the Preferences screen, but you can still keep the downloaded disk images by navigating to:
Ironically enough, I only remembered this again when I was going through my home folder backups, and realised my Caches folder was way larger than it should be.