That's one of the things I am afraid of. I have a couple of people that have Travel Trailers and 5th wheels in my area sitting in their driveways. Some have covers some don't, but I never see them outside to ask about their experiences. So far mine has been without a cover going on my 3rd winter. Doesn't look any worse then when I got it. I have no leaks or see delamination. My only problem was with the awning and separation near the top when I unrolled it this summer. Im getting ready to winterize it again in a couple of weeks. But this year I thought a cover might be nice to have.
Never forget those who gave their lives on 09-11-01. FDNY/EMS/NYPD/PAPD and those still dying.