It is well to remember that glasses should be "on your face or in the case". This will help prevent breakage and lens scratches. I have a pair of Ray-Ban aviators that I've used as my general-purpose sunglasses for more than 20 years. They are on their second set of earpieces (sweat-induced corrosion having eaten one of the originals in two). The habit of putting them back in their case is the only reason they're still serviceable.