I used to have over 100 saves, but I deleted most of them and missed some of my Sims, so I kept starting new saves again downloading the Sims back from my library. This happened few years ago and now I have about 60 saves again. :D
I have a big problem with starting new saves and I'm aware of it, but I love playing different Sims with different careers, aspirations and all kinds of challenges and I hate doing it in the same save. I used to have many annoyances with rotational play in one save and I much rather do it in different ones, even if some of those problems have been fixed now.
I do have few saves with several played households, for example families that have expanded and I've had to move the grown up children (or other family members) on their own and I do rotate between them, but there are still things I don't like. Family members suddenly forget that they know each other and I have to introduce them to each other again is the most annoying.
I've recently been playing with the idea that I should do some "cleaning up" again and I even had an idea of deleting everything and starting just one single completely new save, but I know it's not going to happen. I'm way too attached to my Sims to do it and even if I could just choose one save to continue with I could never make that decision which one.
I'll just keep playing all my saves and try not to start too many new ones. :p