Another thing about cache files is that if you play in Riverview and/or Barnacle Bay, you might have world cache files too. The path to those is Documents > Electronic Arts > Sims 3 > WorldCaches. Not everyone will have this folder, so if you don't have it, don't worry about it. It just means that your computer doesn't use these caches. But if you do have that folder, everything in it is safe to delete. You should have 2 files for each of the downloadable worlds you play.
When these get overloaded in my game, it's a major source of lag in Riverview and causes Barnacle Bay to freeze up entirely. Lately, I make a habit of deleting these regularly, along with the 4 cache files in the main folder. I didn't know about the DCBackup files, though so thanks!
Wow! 307 files in that folder.