What might be happening, since you change households is, that maybe when you are playing one household and the bills don't get paid and then you change to another household and then go back to the first one, it might have been to the stage of the repo man coming anyway, so when you went back, the repo man showed up. Did that make sense. I love to change households, but for some reason, before I get the "no bills ever" with my happiness points, I always forget about those silly bills, so what I have had happen, I left one household, then came back to it and not too long after that, repo man shows up, so that might be what is happening. Pam is right, unfortunately, they do not pay them on their own.
I do know, that if you have a family that is not your active family, they love to get into their formal attire and go out. When I switch household, they are never home and if they have toddlers, there is always a babysitter in the house, which I always thought was pretty cool. Mine likes to go to the lounges and sometimes find them reading at the library.