I had to store my car during the season (late Spring, Summer & early fall) 2 years ago as I did not have a garage. I made sure to store the car on concrete surface and coveredred it with a Wolf car cover I purchased through Summit. It worked great, however I did notice that the cover did wear out pretty quickly. I still have it however I dont use it at all as I have since built a garage that is bone dry.
In my experience, if you are storing the car indoors, in an inactive area, the finish of the car is better maintained by not having anything on the paint or rubbing against the paint unless its being lubricated by water, wax or spray detailer. Despite all the greatest claims of covers, "scratch resistant" "safe for your finish", eventually something will get stuck in the fibers of the cover and scratch the finish. So you end up paying upwards of $200 in some cases for a great car cover that, in my experience, will eventually cause you to regret ever throwing that thing on your car and that sucks.
In my opinion, if you are storing outside, for any length of time, better to have the cover than nothing at all. If you're storing the car inside, I would say forget the cover, clean the car, prep the paint, wax it up with a good sealer like Collinite or even Dodo Juice then hunker down and dream of the warmer weather.