I use the same few clothing items on all my sims. There are some items I really like the design of but the few color selections are all wrong.
Same for traits. Traits in the game do so little to make any difference so I bet I use the a small selection, like 5 or 6 traits on all my sims.
I’d like to do things like make a few sims with clothing/traits/hairstyles that I’d never want to use on sims I care about. But with culling and so few lots I feel like there is no room for that.