I was having some trouble with my game, but because it was not really glitching or anything serious (just unusually slow loading of lots and objects and occasional crashing), I didn't want to do a re-install; I also wasn't too happy of the idea of doing a factory reset because of the hassle of downloading all my store content again. I finally did it 2 days ago, as the loadtimes were starting to be ridiculously long for my PC's specs.
And I'm so happy I did it! It wasn't too much trouble at all (I copied the store content I wanted to keep from the old Downloads folder and just installed them again and they worked, no need to download them again), and it helped SO much. I could almost see my sims cry tiny little happy tears (or maybe it was just the nerdy me) as all the loading and crashing was gone. I put the same save file in and it loads so quick and smooth. I couldn't believe this would work so well!
I hope you don't see this message as a pointless repetition (which it is I guess) but I just wanted to encourage people to try this if their game is not working as well as it used to, I put it off far too long! And there really isn't any harm done if you store your old folder somewhere when you do this. It was so easy and fast, too.