Re: Sims 3 Files - what can I delete

@troshalom Cache files are generally the ones you can delete in case they contain outdated data, as well as xcpt files, which are crash logs. The list of cache files can be found here:

https://sims3.crinrict.com/en/2011/01/faq-delete-your-cache-files.html 

You can also take a look at Crinrict's User Files Explained post if you would like to know what these files and folders do.

As for your Mods and CC, I am not familiar with most of those aside from Nraas, but they generally shouldn't have issues with new Expansion or Stuff packs, as long as they are compatible with the version of the base game you have installed. You can check your base game version in The Sims 3 Launcher, or by opening the Version.tag file in Notepad. If you want to check your Mods and CC for updates anyway, the best way to do it is to look up their creators or, if the file names don't contain the creators' names, look up the file names directly.