I just don't do anything that would make me feel guilty in the game. I spent all my guilt points in Sims 1 and learned not to do those kind of things. Now if Sims do it to them selves - well when ever I left it as it happened - sometimes I felt guilty even then. So I would bring them back in Sims 2 - but I would leave the memories in that game so they were not erased but they'd get a second chance. I wish they still had memories like that in 4 - as it worked for me with that. Now I just try and at least try not to let them die before they've had a decent life. Not always easy with some Sims - lol.
But mainly that is the only thing I interfere with is early deaths. Anything else that happens - well it happens. Death before someones time is a personal thing to me - so I have to draw the line there. (I never intentionally do anything bad to my Sims though - as I said I learned how hard and guilty I felt once in Sims 1 for trying)LOL.