Probably put this in the wrong place...I was super stoked to get 15,000 articles of clothing so I could get that achievement out of the way and finally prune down my wardrobe to the items i actually like and want. I find it hard to get dressed when i have 15,000 items and only care about 100 of them! However, now I'm between a rock and a hard place because i want to get rid of items but am afraid to get rid of anything i might someday need, so I find myself keeping everything! Is there any easy way to see what i need to keep for other achievements?

All the wearable achievements are under the same section of the achievements page, but there is no way to tell what might be released in the future. It's up to you to decide what you want to do with your wearables, some people sell them, or stick what they don't use in their vault, or just keep it all :)

I once tried paring down my wardrobe. Sigh.

I took out a bunch of things that I thought were ugly or useless, or both and stuck them all in a shop that I didn't price. I figured I'd leave them there for a month, maybe two, to see if I found myself needing any of the items. Then, once I was sure I wouldn't need them, I'd just autoprice the shop and sell it all.

Well it didn't work out that way. I ended up going into that shop and putting stuff back in my wardrobe every other day. In the end I put everything back.

I made an "ugly" drawer instead and stuffed everything in there. I still use that drawer regularly.

As for wardrobe items needed for achievements, SubetaLodge has some custom checklist suggestions that are based on achievement specific collections. It doesn't include some of the most recent achievements, and of course, as said above, you never know what new achievements Subeta might introduce in the future.