The hardest decision to me is which of my sim kids is going to be the heir and stay with mom and dad while the others move out. It's always so hard for me to let the "extra" kids go. I don't play rotationally, I have tried several times and it's just not for me. The kids who move out always stay in touch, but I miss playing them every day and when they have kids, it nags me that those kids will not have me to raise them LOL.
If I could just learn to like playing a rotational game, this problem wouldn't exist. :'(