I was a super happy camper for the last 15 years with NO sunglasses at all. In the summer I would come off the water with a headache, but I thought that was normal. Then my buddy offered to sell me his Maui Jims because he bought a new pair so I bought them for $30. They were great despite a couple of scratches. That is until one day I decided to take a nap on the couch with them in my pocket - not the best idea but hey, I need to catch some zzzzzzzz's. Broke those mofos in half at the nose piece and threw them away (mistake, could have sent them in).
So after that I decided on cheap sunglasses. I was going to get some Bimini Bay's and saw the calcuttas, which I liked pretty good so I got the calcuttas for $23. They were fine for the 1st week and the 2nd week. Then we went kingfishing and on the way back to the hill I got sprayed pretty good in the face the whole way back (should have taken my boat LOL). When we got back I stuck em under some warm water, a drop of dish detergent, and gently used my thumb to clean off the salt. The mirror coating came completely off one lense. So that pair cost me $10 per week I owned them. That is when I decided I need the good shades. And like RKC said, once you wear the good stuff its hard to go back. Plus when you pay big $$ for shades you tend to take better care of them, except on Thanksgiving.