How Much Planning Goes Into Your Gameplay?

I have three general scenarios I stick to-multi-family rotational, single family, single sim. Which one I'm going to play, and what my sims' names will be is generally the extent of my new save planning. As children are born in the game, I usually plan what their futures will be, but loosely. I usually play on long life, so I've usually changed my mind about a sim's future plans one or a dozen times by the time they've grown up.