Always curious what others consider important in their SHTF/TEOWAWKI garb. I've put back "enough" to where if new items were not available I could get by for a long time. Here are a few things I took into consideration as I bought and would like to see your thoughts.
Buy them sooner than later and break them in. Most importantly, look for sewn-on soles rather than bonded ones. IMO they last much longer. Was in our local market a few weeks ago and watched a good brand set of day hikers lose one sole as the owner was walking. Asked him how long he had them and it was less than 3 years. Had the same thing happen to me with a set of 3-4YO day hikers on the trail but fortunately as I was closing in on the parking lot after the hike. OTOH, have 2 sets of sewn soles (Lehigh & Chippewa). The Lehighs lasted ~25 years before I had them resoled. They weren't worn through but had lost the lugging. The Chippewas I got in 1996 and they are starting to get to that point. Speaking with my son about this all bonded stuff, he considers them an item that you must replace periodically.
My own pref is Wrangler "cowboy cut". So far I've had great experience with them and gotten several years of hard wear out of each set I've bought. Levis were blowing out within a year, sometimes less and I stopped buying them. It takes several washes to get the Wranglers to wearable condition but they wear like Levis of years past. Price is good too, generally less than Levis although can be tough to find. I found them at Tractor Supply.
Not a tactical one, the type I can wear exposed and not get second looks. A vest slowly worked into my cold weather wear as I can get by with much lighter outer wear now, typically a rain shell and/or hoodie even when there is snow on the ground. I am looking for a replacement to the one I had, an older all wool one with a couple zip pockets. Very basic style, did not stand out when my outer wear was off and could hold a lot in the pockets.
Pants, coats, shirts, gloves, socks, etc. the variety, especially from Europe, is amazing, A lot of it is wool and it wears like iron. If you carefully shop you can assembly daily wear that does not look make you look like a mall ops ninja. However, it may take you a few tries to find things that fit well. Best if you have a local surplus store where you can try them out first. Well worth the effort though. I've got a few pieces that see regular use but were purchased at least a decade back.
I am a huge fan of Ray-Ban, even the post Bausch & Lomb Luxxotica China ones. I cannot tell a difference in the optical quality. However, there are many other Chinese choices with great optical & build quality at a fraction of the price of branded ones. I've got multiple back-up sets in case of loss or breakage for the cost of a single set of new Ray-Bans. I have those too but do not wear them where they risk getting trashed.