I try and follow the principle of ‘fashion is temporary, style is permanent’ and have a few rules like not impulse buying things that look nice on their own but aren’t that versatile when it comes to pairing with the rest of my wardrobe. Buying tends to either be to fill a gap in my wardrobe/have a need for something I didn’t previously or just to replace something that’s given up the ghost.
I buy good quality basics and staples - which doesn’t always mean expensive - look after them as far as washing and cleaning them, properly and wear them until either they fall apart or bobble too much, get damaged accidentally or in my journey to get more jacked they no longer fit properly.
Can’t stand fast-fashion, buying according to trends or just buy-cheap, buy-twice/thrice etc.