The crazy thing about no longer new/ trendy items is that they are mostly clothing, and the vast majority of clothes will go back into style if you hang on to them for a few years (between 3 and 5 will generally do it). I understand that a lot of people don’t have the space to do so, but that’s unfortunate because used clothes are very, very reusable. Even those clothes that don’t completely come back into style can generally be obscured under sweaters or shawls.
I use my old clothing like this and I like what it does for my wardrobe. I end up wearing clothes that don’t look like the trendy clothing that everyone else is wearing at the moment, but that also don’t look like “last year’s/ season’s clothes.” Also, I couldn’t afford to buy a closet full of this season’s clothes. I buy the occasional new shirt or pair of jeans and call it even.