A cover should be tailored for the car, otherwise it will move too much in the wind. It should be PROPERLY breathable, with figures available from the vendor, hence should not have an instruction to remove it every few days-a properly breathable cover can stay on for months at a time. UV resistance is also very important-a good cover fabric will wihstand the Arizona sunshine test for 2 months, equivalent to at least 5 years use in the UK, it should also be a good UV blocker to protect the paint and plastic parts of the car.Low UV resistance means that the water resistance and the mechanical strength of the cover fabric can begin to degrade within 2 months. There is no such thing as 100% waterproof incidentally; any vendor quoting a percentage of waterproofness is talking nonsense, the water resistance of a fabric is quoted in millimetres, and a good figure is a metre. There are only a very few fabrics worldwide that meet these criteria(and they are not from the Far East), and I import one of them to use in my business.A proper fabric to make even a Clio sized allweather cover costs me almost £100 alone, so that should put into perspective roughly where the retail price of a worthwhile cover should be.