I bought a Noah Covercraft car cover, I use it daily for 10 years, the best way to use one is to make sure the car is cleaned. I use a California Duster, to dust of the car in the morning and in the evening, then I do a quick wipe with Adams detail spray or waterless wash. I don't like the thin car covers because those are only indoor use, the cover I have is bulky but once you learn how to fold it, it's not so bulky and is easy on and off process.
The Noah car cover is thick and help protect the car. I bought mine through AutoAnything because they always have a sale for 20% off and their prices are better than going through Covercraft.i don't mind the xtra work of using a car cover becuae I enjoy my car therapy sessions.
So bottom line it's up to you, and your own maintenance routine and habits of taking care of your finish.