I put one of the 3M clear kits on my Toyota truck to prevent stone chips. I used some left over on various things including my bicycles. There is also a thick clear vinyl tape that can be had at auto parts stores for repairing vinyl sets. It is thick, invisible when you put it on, leaves no residue when you remove it and it is cheap.

I hate scratches, a clean, well cared for machine is a happy machine. When I see a scratched up bike, car, whatever, it tells me it has been ridden hard and put a away wet, abused and beat. Just me. Of course it is hard to use something without being obsessive and not get some wear and tear representative of normal use.