In TS4 I've been playing one family line for several generations. The hardest part is picking which child in every generation I want to move forward with but eventually I've been able to pick one (...sometimes two...) who will either move to another house and the old family must fend for themselves or the chosen one will continue living in the family home and possible other siblings will move away. The sims I play all end up having their own personalities (in my head anyway...), goals and different lives so I don't find it at all boring. Because I have MCCC the sims I don't play go on with their lives on their own. ...and there may have been some light inbreeding if they happen to meet a relative of theirs that I really like (looks & traits)... But hey, it's just a game ?