I make anywhere from 1 to 5 outfits per category, usually at least 2 everyday and sleepwear outfits and 1 for the others (generally 3 sleepwear outfits - 2 normal and 1 for *ahem* certain other purposes), and rotate between them when I or the game feel like it. Occasionally I'll switch outfits around when they age up, but that's more likely to be teen-YA or adult-elder than YA-adult (since I generally imagine, especially if I created them with kids, their style wouldn't change that much).