* Please note: I am not an expert on any of this. Please wait for one of the Flynn's before doing anything that I say I have done below.
These are things that I've done in the past and my understandings of them.
I've deleted the xcpt files from my game in the past. They are the files created when your game crashes.
WorldCaches - if you play in a world that you have purchased from or have received free from the store (eg Monte Vista/Dragon Valley/Riverview/Sunlit Tides etc) a copy of the world file is put in here so that it loads quicker when you return to it. I have deleted these items in the past.
Screenshots/Recorded Video - these directories contain the screenshots (<C> Button) and videos (<V> Button) you take/record during the course of the game. If you copy them/save them elsewhere or have finished with them (or in my case, click V when I mean to click C), you can safely delete them.
Saves - The Saved Games - I don't know enough about these to say what to delete/keep here. I always do my deleting of the games from within the game itself on that screen where you choose to start a new game or play an existing game
Saved Outfits/Saved Sims - This is when you save a sim/household to bin and where you modify outfits in create a sim. Once again, I don't know enough about this more than that to suggest what is safe to delete
User Presets - this is where the stuff you save in options in game goes. I deleted this once, and it all reverted back to the default settings.
The other things, I really don't play around with, I'm sorry.
Once again, I'm not an expert on any of this, and I'd strongly suggest you wait for Mr/Mrs Flynn to chime in. Here's a nice treat for you MrsFlynn
*Leaves something virtually tasty behind*
