To further the discussion, I like waxed leather for knife sheaths and axe guards for the protection of the steel tools against rust, not necessarily for the upkeep of the leather. The leather sheath is replaceable if the knife remains in good shape.

Leather shoes and boots get wet, dried, and eventually replaced as they were out. I still carry my hunting knife from 35 years ago however my boots from that period are long gone.

Dive knives are a different matter, they all get trashed after time. My son asked me what happened to your Model 16? I went diving all the time. Work, sport, and police dive team. Sea water at depth does a job on the them. The Model 5 I carried for a rope knife survived just fine.

For me the waxed leather is just extra insurance. And I like the look and feel although it can be stiff at times.

My leather handgun holsters were not waxed.