i think one thing to keep in mind with BIFL is that it's gonna be painfully expensive, and we tend to have a skewed perspective since a lot of what people buy these days is second hand and thus nowhere near the original sale value.

Like has been said for new BIFL stuff you want to look for business/industrial stuff, or handmade things from passionate people, which is not cheap.

I think it's pretty unrealistic to expect most of your things to be BIFL unless you can get second hand/inherited things, i'd say think about what things are most important to you and try to invest your money into those few things and find ways to make everything else as minimal and sustainable (and cheap) as possible.
For example people in the medieval era and before generally just wore simple leather turnshoes in the warm seasons, which were fully expected to wear out and they'd need to slap together a new pair every now and then. But that's fine because literally all you need to make them is some crummy leather scraps!