I wore off prescription glasses for sailing five years ago after donating one last pair to Neptune. Its not just the cost, but also the mental angst you feel. If underway, they are just gone. If at the dock, youll be fishing for them with a net or going for an unscheduled swim. Retention cords help, but if Im also wearing a cord on my hat, annoying tangles ensue. On the other hand, when a pair of drugstore glasses goes in the drink it doesnt ruin your day. And then I learned that the local dollar store had suitable glasses for a buck; Im wearing them as I type this. I wont win any fashion awards, but when I drop them or sit on them, its less bothersome than spilling a soda. I like that.