Like most other topics here on the forums you'll have responses from those of us who do cover our rigs and believe it to be advantageous and responses from those who consider it a terrible waste of $$$, claiming RVs are "made to be outdoors". That may be true but regardless water intrusion of any kind is the worst enemy of every RV and unfortunately sealant used to prevent this water intrusion does fail with time and exposure to the elements. I've winter covered every trailer we've owned that wouldn't fit in my garage to help protect the sealant AND the awning from the constant snow melt / refreeze we see here in Ontario during the winter and wouldn't ever consider not using a cover. Our first was an ADCO AquaShed, second that we had for 6 yrs was an ADCO Tyvek, current one (3 yrs so far, no issues) is an ADCO Designer Series Tyvek. The key is the installation - pad any and all sharp corners and strap the cover down so it can't blow around and you should find the RV just as pristine in the spring as it was in the fall when you covered it. :)