Depends on the application. If it's for my bush knife, I want kydex, since I don't have to worry about it, and it can easily be attached to a backpack strap, belt, whatever, and I don't have to worry if it gets rained on. For pretty tools that get carried to nice events, leather. For anything else, I don't really have a preference.Speaking of bushknife sheath, anyone know how to make kydex stuff, cause currently I have a leather sheath, and it is driving me nuts!
For in town I like either leather or nylon, for outdoor thou leather tend to get damp, plus the button enclosure isn't secure enough, so nylon for that.I tried kydex but never quite liked it, it's too rigid, when mounted on belt it interfere with body movement when bending sideways. But then again all the ones I tried are for medium to large fixed blades.
You can do a dip on leather , a combo of beeswax , parafin wax and raw linseed oil . melt the above , dunk the piece , put in an oven at no more than 170 F for no more than 10 mins . Oil/wax gets sucked into leather - no maintainance ever ! Downside , in extreme heat , 40+C , can bleed into clothing . I have made a couple for CF Gromans ( back when they were issued ).Sailors used to dip sheaths in tallow and wax , I suspect if the tallow proportion was wrong , the whole issue would go rancid .Chris