Hi. I don't use a cover for the following reasons:
1. I'm in my later sixties, and I don't get up on the roof as easily as I used to. Man-handling a cover would be more difficult now.
2. I have a solar panel on the roof that keeps my house batteries topped off and I don't want to cover it.
3. I try to drive the RV at least monthly to keep it "limber". I don't want to keep taking the cover off and on. In January, the weather is often bad, so that is one month that the RV usually sits.
4. In February, we are off to Florida. Sometimes the driveway is covered in snow and ice when we leave, so I can't imagine what the roof of the RV would be like trying to get a heavy cover off the rig.
I think using a cover depends on your climate and how often you take out your rig for a spin.