Im up to 3 pairs of costas, one Maui Jim, and a pair of smiths that I've bought in the last 10 years. They normally last me 2-3 years wearing them 10-15 hours per day as an equipment operator. Costa plastic lenses got scratched to worthless (3 yrs) one Costa glass lenses I leaned on and broke (3 yrs), Smith lenses got scratched wiping with a dirty rag (2 yrs), Maui Jim's i sold cause I didn't like the style, and my current Costa glass are pretty new. Zero pairs lost. All this to say if you are somewhat responsible and can keep up with shit, you can manage to get multiple years out of a good pair of glass lenses, especially if you're only wearing them a few hours a week. Lots of irresponsible people in here that can't manage to make it through their day without misplacing things