I sometimes have to restart a particular save. Something goes awry, somebody dies way before their "time", as it were. Sometimes, my save file gets corrupted. Plus, since I'm generally replaying the same cast of characters, if you will, I have to rename the saves. I also have the habit of doing a Save As for each gaming session. So, if need be, I can do a save recovery, which for me is better than starting the entire save all over again from scratch. I really don't know how many saves a saves folder can handle, either.
Sometimes, the new save is to test a mod new to me, so I don't wreck the Main save, too.