I play almost exclusively like this. Normally I start with some sort of orphan legacy or a household of non related friends who go to University together and then all branch out with their families. I'm currently on Gen 6 in my longest save file, have almost completely rebuilt the world, and have about 8-12 families I rotate through.
I have auto aging off completely for this save and sometimes I'm not super thrilled with one family or another so they get skipped over and every once in awhile, I go through every single household and age them up several times (or kill a few in different ways to keep my numbers down) to get to the next generation of young adults. It's really cool to see how they pair off, have kids of their own, and then have their grandparents and greatgrandparents living in the different siblings' households. I love seeing sims from birth to death and I love seeing how far back and interconnected their family trees get. I only add 1-2 sims each generation to keep the bloodline fresh.
The in game family tree isn't super useful for understanding familial connections so I made my own in Canva using their whiteboard and I'm excited to update it for this next generation
