I am on a tight budget so usually shop:-
Uniqlo for everyday basics (better quality and cheaper than Gap, often with good sale bargains), especially their base layer heattech tops in winter and cotton t-shirts in summer.
M&S for everyday knickers, workwear (black trousers and plain shirts), and the odd surprisingly decent accessory purchase.
Zara & Mango for nice casual wear (tops & dresses), although quality has reduced drastically in last few years and trousers are always stupidly long.
H&M and Topshop less and less so. Tend to get one or two fashionable summer holiday bits and that’s about it now. Usually feel disappointed after looking round.
Monsoon, Whistles, French Connection and Coast sales for special occasion dresses or going out tops.
I buy a lot from EBay these days as cba with traipsing round shops and can’t afford full price for items like winter coat, knitwear, boots etc. Also I’m finding the older I get the more bothered I am about quality, so will check for natural fabric content and care instructions (if dry clean only forget it!). I also notice I’m ironing more as I feel so much more put together in clothes that have been ironed vs those that haven’t.