If it makes you feel better, you can keep a backup of the folder and test it yourself.
Basically, you go to your My Documents-> Electronic Arts-> The Sims 3-> DCbackup.So I deleted them and my game played a lot better and faster. I tried many things and mods to speed up my game until I found out that the problem was caches holding all the items used in game for easier access.
Not to mention how long it took it to start. sluggish, that it was painful and annoying to play. I'm personally addicted to clutter, it's never enough clutter for me. Installing mods for The Sims 3 can be very tempting where you'd end up just downloading a whole bunch of stuff, and eventually cause your game to lag.
