I cover mine, most people do not. Covers, good ones, cost from three to five hundred and last from three to five years. If you are covering for the winter and do not expect to move the rig then one of the most aggravating thing about cover is avoided; you do not have to take it on and off a lot.
Depending on wind and location your cover will chafe at the edges. So far minor buffing has handled the chafing I have received. You cover will tear, I patch mine by sewing.
I live in Seattle and store during the summer, so I cannot comment on the effects of winter but I believe the cover would protect your rig well as mine has been protected. When I remove my cover to travel for the winter travel the wax is fine it is not even dusty. I store in a lot with about twenty other rigs, only three are covered. Mine looks new the other non covered ones show some age.
When I cover my rig it covers the solar battery minder as well so I have to go periodically to run the generator to charge the batteries. Or I could remove them and charge them at home. I suppose for winters you remove your batteries.
On balance I am glad I cover my rig and would do it again. I don't hear too many complaints however from folks who do not cover theirs.
I do all my own stunts
03 Dolphin LX 6355, Workhorse W22, 8.1 vortec, 04 CR-V, Blue Ox, Brake Pro----Norm, Barb and
Doc(He's a PhD)