I probably overbuy. Lots of ways I've become crunchier, but clothes are a "thing" for me - always have been, always will be - my mom and dad are both clothes horses, as is my Nana....things didn't have to be super trendy or brand name expensive, but we like our clothes and we like variety. Sooooo, that's where I'm coming from.
I like them to have 2 weeks' worth of outfits (that includes school and play, we don't have uniforms), plus one "nice" outfit for the rare occasion (like once a season) we do something more important/fancy. That 2 weeks' worth will include jeans, track pants, and a couple pair of khakis for DS, a couple dresses/skirts for DD. I get 5 sets of PJs each, they wear those twice before washing. Each has a sweat jacket, a slicker (it rains a lot here), a windbreaker, a fleece, and a midweight jacket (we are very warm people and do not need heavy winter jackets though it gets pretty cold here, we just layer the fleece under the midweight if we need to). Each gets 1 pair of slip on sneakers, 1 pair of tie ons, and 1 pair of "fancy" shoes per season. Then in winter they get a pair of hikers to muck around in, and snow boots to play outside. In summer they'll each get a pair of sport sandals. Winter they get a snowsuit, summer they get 2 swimsuits.
When the seasons start to change, I'll take half the previous season's stuff away and bring out half the next season's stuff, for the temperature fluctuations. We don't get into pants until almost October too, but then we hit full on winter until at least March.
At least I have a system now - I used to be worse than this, this is actually way better than I used to be say, 3 years ago. Back then I was BAD, like....BAD. So many clothes and shoes. I guess the good part is that a bunch of my friends with younger kids get all the handmedowns!