I've always cover mine in the fall before the leaves fall and keep it on during the winter months. If sized correctly and properly secured you will not have a problem with the painted surfaces. They do a good job keeping the snow and ice off the top and let the moisture pass, so no mold problems in the spring. I have had good luck with the ADCO Aqua-shed covers. The first one was sold with the MOHO after 3 seasons and the one I currently have is on it's fourth year and still looks good. The next (retirement) home will have an RV garage, but until then I will continue to use a cover.
Lou
05 Travel Supreme Envoy