They last a few years. Also, the fit must be really good, or any part of the cover that flaps in the wind may do more damage to the surface of the MH than the elements do. Good luck!
2004 Tiffin Allegro 27.5 ft. P32 18,000 lb GVW. 8.1 liter. Workhorse chassis built May 2002. 21,000 miles. 2012 Jeep Liberty Toad. RVi2 brake unit.