I live in the sunny south and most RV covers here don't last more than 3 years. I have had the Tyvex material before, and I finally brought a 100% polyester cover from Eevelle called the GoldLine model. It was very expensive, and very heavy, but has last more than 5 years so far. I found them on Amazon, but you could Google for that name brand also. Camping World might also have them. They weigh almost twice as much as the "lightweight" covers though, so be prepared for that, as they can be a challenge to tote up a ladder. I usually take one end of mine up the ladder with me, and then drag the rest of the cover up onto the roof. I cannot lift the entire cover and climb the ladder at the same time.