I almost always play with my simself. I've got a current game where I'm fairly close to becoming an elder and I think this time I'll just let that, and what comes next, happen. Usually I turn myself into a spellcaster, vampire, or werewolf before I become an elder because I don't want to watch myself die but then I get bored with being immortal and stop playing it.
Longer term, I've started a save where, other than my simself and those EA sims I like enough to let into the save, every sim is a character from some sort of spoopy TV or movie (Ghostbusters, Buffy, Dark Shadows, the more spooky corners of the MCU, the Addams Family and the Munsters, etc). I say longer term because I want to makeover all the pre-existing sims and rebuild as much as I can to fit the theme. The odds are good I'll get bored with all the building, though, and just download a bunch of lots when people have uploaded enough of them.