Nannies!

I've never hired a nanny in TS4 and the one nanny I hired in TS3 turned out to be a very dedicated kleptomaniac . If you want a live in nanny, you could move in a young adult sim and call it an au pair. Make sure they are from a different neighbourhood, give them some pocket money every once in awhile, and pay for them to have some classes to increase some skills.