No shoes are truly BIFL if you wear them regularly, but these come close

https://lemmy.world/post/44501255

I can’t remember if I heard it here but I have heard (and feel, anecdotally) that cycling between wearing two different pairs of shoes leads them to lasting longer than if you wore one pair until they fell apart then a second pair until they fell apart.

I don’t know how that could possibly work unless giving shoes a “break” rather than wearing every day extends their life somehow.

My evidence: I have had a separate pair of running shoes and walking shoes for a few years now.

AFAIK, it is the leather ageing faster, linked to bacteria growth due to humidity. Cycling between 2, ideally 3 pairs, allows the shoe to dry and kill the bacteria in between.
In addition to the leather stuff the other commenter mentioned, foam gets compressed during usage (especially running shoes with a lot of foam). It can take several days for the foam to recover. If you run in the same shoes every day, you aren’t getting the full benefit of the foam, and you are basically beating it while it’s already down.
Aaah that kind of makes intuitive sense

That’s only a requirement for leather.

I live out of a backpack, so I can only own one pair of boots. I switched to synthetic, and my boots last decades instead of years.