This turned into a stream of consciousness, and a lot of this applies more easily if you're male or dress masc, but to build on what others said about custom clothing...

With clothes it's better to buy natural fabrics - from a longevity point of view, to sustainability, to breathibility, you're going to get things that last longer if they're made of natural fibres instead of plastic shit. Easier to repair a hole in a wool jacket than in a nylon windbreaker, and that polyester suit looks bad anyways. Yes it's more expensive, but that often means the manufacturer is spending more time on the actual manufacture. Yes it can be a pain to maintain - leather footware needs more care than sneakers, you won't be able to throw things in the dryer - but it'll look and age better for it.

Obvious there's a place for technical fabrics - companies like Arcteryx make at least nominal overtures to sustainibility and long-term planning. Personally, all my tech shit is vintage ski stuff, hand-me-down fleece, or military surplus Gore-tex. Hiking or canoing outfitters can make awesome bags if you need something heavy duty, but the good stuff is made by old guys who are literally dying out, so you might have to hunt around (I'm thinking of like Cookes Custom Sewing).

A lot of companies that made conscientious, practical clothing and stood by their product in the past can't really be depended on these days. LL Bean stopped their lifetime guarantee. Filson was once sewn up by little old ladies in Seattle, now it's owned by Blackrock. Duluth sells $700 backpacks and donates the money to the Trump campaign. All those companies I would only buy second-hand examples from earlier eras. So you might have to do some digging to find the right thing made by the right person. For many of these guys, they started as workwear companies for blue collar workers, and I'd recommend finding contemporary examples - Tough Duck is a union-run Canadian brand that does Carhartt but better, for instance.

For anything more than the most casual footwear (boots, dress shoes) go for something a bit more expensive and goodyear welted, and find a good cobbler. It's better to spend $300 on a pair of shoes you can get resoled and looking like new than $150 on a pair of shoes that will need replacing every two years.

Jeans you get diminishing returns after $150, but living in the faded golden age of raw denim there's no excuse to buy a cheap pair that'll fall apart - find something in your price range that flatters you made by some hipster yammering on about selvedge lines and how many ounces the fabric weights, and don't wash it in the washing machine. In fact, wash everything you own in cold water and on the delicate setting, and don't use your dryer if you have the luxury of space to hang dry - your clothes will last longer and look better.

Long and the short of it: do your research, buy used if you can, don't buy big box sweatshop trash if you need to buy new, it's better to spend a bit more on something sturdier, learn to do your own repairs, cultivate an aura of radical DIY sustainibility, and most importantly be uncompromising about who you give your money to and what you put on your bod.