The use of RMP started many years ago on boats in Florida before it migrated to RVs. Most sit out in the sun year round with no issues from UV. In August it will have been on my 5th wheel 3 years. I did add another coat to the front cap this spring as it was looking a little dull. The rest of the unit still only has the original application. The key to using it is surface preparation. This can't be stressed enough. Too many people give a quick wash job and then put the RMP on. It just doesn't work that way.