The only time I bother with townies is if I notice a particularly weird looking or good looking one.
I'll keep the far and few between good looking ones, change their outfits, maybe hairstyle, but rarely mess with physical features. I don't ever change names unless it's something I can't pronounce or a duplicate. They get saved and put in my custom template to wander around, used for a friend/love interest for my Sims, or to continue working in their NPC roles. For instance, I have two mail ladies that I like, a few vampires and one townie that ended up being the spouse of my Not So Berry founder.
The weird ones get their photo taken and then probably either left to roam or deleted along with other townies who have annoyed my Sims. Otherwise, I just leave ordinary, regular townies to their own devices and ignore them until there's too many and go on a periodic townie culling spree. *shrugs*
