I am a Cop and prior military guy, my sunglasses live on me and go through more abuse then they should ever be subjected too.  These hold up like no tomorrow, and I typically get them to last at least 8-10 months.  That may not seem like long, but between fight calls and drunk people, there really is no telling.  I alternate between this model (zander) and the Recoils, just depending on whichever is cheapest on Amazon at the time.  Bolle has never let me down.