I've actually done this, and it's very rewarding, especially if you have things left in the game that you haven't discovered yet.
I need to buy the games all over again because when we moved, I lost my discs (and therefore serial numbers), so I can't play them. But this is how I intend to do it, to give it that feeling of freshness.
I'm loving TS4, and personally prefer it over TS3, but I'm also generally a Mac user and was disappointed that there was no Sims 4 for the Mac.