"mightysprite;c-18223598" wrote:
Teens attend school in their club outfits two days a week. Chess, computer, football, cheerleading.
There's some slight oddness to this, as teens sometimes wear an outfit inconsistent with the afterschool activity they belong to. I have yet to test it, but I think they may stick with the activity uniform of the club they initially join, if they decide to change activities at some point. (Speaking of the behavior of unplayed sims only.)
Also, never enter CAS when your teen is wearing their activity uniform, as the game will overwrite the outfit in whichever outfit slot they currently have active with the club uniform, and you'll have to recreate it.
If a teen is famous enough, and has a particular fame perk, other students can also choose to copy their wardrobe autonomously. This can sometimes have very funny results, for instance if you have a quirky sim who likes to come to school in bunny slippers.