I had a live-in nanny before who also did the cleaning and cooking. Whenever the house was a mess and guests were coming, I just clicked the floor and selected "Clean House". Another sim to help out is cheaper than those worthless babysitters who just stare at the plasma all day. (It's tempting for them for some reason.) I'd rather pay by the hour than pay $75 for a teen to watch the tv or read a book. Oh well, better than those Sims 2 elderly nannies. Anyways, my live in sim didn't cost much, being a green thumb she just gardened things such as apples to pay for a bed and food. It's actually much cheaper, and you can control the sims to take care of the babies. She would just carry around the babies, and watch some tv in a sparkling house and amazing food in the fridge, and care for the baby when it needed something. Mules work like a charm!