Covering your travel trailer

Oh, I almost forgot. Do not wax the decals! You will be sorry.

If you do not have a garage/barn for your camper a cover is a must. The most important thing it does is keep the sun/UV from damaging the camper. This is better for the roof, sides and especially the decals. Keeping dirt/water off is just a secondary benefit. If you want your camper to look good when you sell it keep it covered when not in use!
If you see a good looking older camper in a campground then it has been covered or in a barn/garaged. Maybe a carport if you get full sun protection.

I cover in storage for any perior of two weeks or more.

Regardless of the cons you hear about it, pretty much any cover is better than exposed to the elements.
I found with the soft covers, snow was harder to remove off the roof and freeze thaw resulted in large icicles that pulled at and tore the sides of the cover. (Well, I tore it trying to remove the ice...lol)
If you get a bunch of snow, I’d recommend a plastic tarp over the soft cover. At least just over the root area, much easier to get the snow buildup off.

I covered out last TT every winter for the 13 years we had it and would absolutley do so again. Keeping the weather off them virtually stops the clock on aging. One caveat, if you live where its very windy then they may not be a good idea, or at least that's what some say. They're fine for the occasional blow though and I never had a problem.

Here's what our old TT looked like the day I traded it in. I attribute its like-new look to covering and waxing it regularly.

You will get different opinions. I think a cover is a good idea.
Make sure the TT is clean before you install the cover. The cover should be snug fitting.

I have never had any damage from the cover rubbing and we get a lot of winter wind in our area.
It does help keep your rig cleaner.

I no longer cover, had significant mildew on top and interior of trailer.
We did however have record breaking rain that particular winter, took HOURS to clean.

I now use a dehumidifier and rub down the entire exterior with 303 UV protectant.

Your situation may differ as our trailer sits at home plugged up.

I'm thinking I may cover if off site with quality cover, several windows cracked.

Cover mine every winter. I give it a good wash and it looks nice and clean when pulling the cover off.
I had an ADCO cover on my previous 5er for 6 years and when we got rid of the 5er I stuffed the cover under the bed because it had several more years left and I didn't need it.
Bought another ADCO for our present TT. Put tennis balls on the gutter extensions to keep it from tearing.
I have owned trailers before and not covered one year and they were a mess to clean up in the spring.