I always keep the first and last saves from a character that I invested some time into. Before I archive the save, I put the character somewhere in the game for "retirement" and then archive the two saves and then delete all the other ones (I make lots and lots of slots when I play). I will pull them out of retirement or start over with them as the case may be. Usually for a mod that requires a higher level character or when I want something that is already developed to explore with.
Note, in this game, I never do the dungeon tutorial, instead loading up that one save from before I exit the sewers, I make my changes, then create a new slot. So, that's my first save of the character.