I have looked into a coating to go on my roof over the rubber membrane. Yes its time to do something prior to a leak developing. I am getting mixed reviews from tt repair guys on whether this would do...
How old is the roof? Any RV "rubber" roof if properly maintained should last well over 12 years. Is it just because you are seeing the white top coat coming off that you think the roof is shot? Or is it because you have lots of leaks. If it is truely shot, then a tear off and reroof is going to be your best option.