In our household we identified what type of clothing we were most comfortable in and wore the most, then we compared them with what we thought we would need in a post apoc environment and realised (A) the need was similar (B) workwear was ESSENTIAL. So we tend to find the workwear we like ( Approach shoes, Jeans, T shirts, Polo's Hoodys, Fleeces, Soft shells and at least one Parka each. Socks, Smalls etc) and bulk buy when we find them on offer. We are not bothered about brands we favour durability and comfort, so for example my normal attire is a pair of approach shoes, cotton socks, Denim Jeans or Cotton Cargos, Good quality Leather Belt, Polo shirt, Hoody if its cool, Modified Soft Shell outer (extra pockets and loops) , BB cap, tactical gloves if needed. ONLY Cotton underwear though some slightly elasticated for comfort is used .
I tend to buy footwear for myself in sixes if they are on offer, I buy ten new Polos each year but retain the previous years as a reserve. I buy five or six pairs of jeans each year also retaining the previous years, Two Hoodys and one Soft Shell a year again retains the previous years.
My wife prefers fitted T shirts, Son prefers Loose T shirts, Daughter anything she fancies.
Many of our clothes get modified with extra hidden pockets, Jeans sometime get extra belt loops, Jackets get any damn hook loop velcro removed as soon as we buy them. ( Velco being the enemy of silence a tactical neccessity) .
Clothing and footwear maintence is obsessive in our family, we cared for clothing and footwear lasts much longer than neglected clothing.
The hardest thing to source in the UK is good quality 1.5 in wide leather belts, most of what is available is far to soft and flexible for sustained use and carrying knives, pouches, holsters etc. I'm not keen on tactical nylon belts for the fire risk issue, same for most synthetic clothings ( Cept Soft Shells)