I was a wildland firefighter in Montana for a while and the nomex jeans that we wore held up really well. We spent a lot of time on all fours, in thick brush, and scrambling over rough terrain. We would wear one set of clothes for weeks on end, just to see who would cave in to the stench first. I literally wore out a couple of sets of leather work gloves but only wore one set of nomex all season.

I never saw new nomex issued. Replacement jeans and shirts were always used gear from the district's fire cache. There's no telling how many seasons it was issued.

Ed