I have a fiberglass roof that is 12 years old and no leaks or problems. I sealed all seams on the roof a couple of years ago with Eternabond and no leaks or problems. I wash my roof before every trip and when I return.
I tried Red Max Pro a floor coating, re coating it every two years and it lasted for about 5 years and then started to flake off. Now it is back to where I started. I originally waxed it by hand, but that grew to be too much work. During that time it sat out in the sun most of the Summer and that is hard on anything. Now when I am not using it I put it into my VersaTube RV shelter.