We bought a cheap cover for our 21' class C 7 years ago. After 1 winter, areas
were wearing through from tieing every loop under it tightly. We thought we had it tight enough that it wouldn't wear so bad, it did. The next winter, we tied 1 rope under the center so it couldn't blow off, then (this is the key) tie a rope all the way around the camper, right above the bumpers, and cinch it tight and walk away. Will do this again this year with our new cheap cover. By doing it this way, you don't have the tight pull at every corner and obstacle. Last one lasted 6 Minnesota winters.
Brian