One system I sometimes do in big household is that I take turns on which sim I focus on. I'm not allowed to switch to another sim until I've granted one of their wishes. Usually they wish for pretty simple stuff, but it's a nice way of getting to know them and you can have several rounds. It's fun to see what the sims are up to when you get back to them.
Sometimes when my sims start fires I watch and wait if anyone is smart enough to put it out. Otherwise... one sim less. Okay I wouldn't do this to my favourites, but I play a lot of families so there are some spare sims. Two sims have died this way.
I also have some rules for my rotational play which vary from one family to another. My escort sims get "kaching" every time they woohoo with someone new... In my mafia family the heir must be girl and their bodyguards come from a certain bloodline... Few houses live without electronic appliances... that kind of stuff.
