I have the OEM car cover and only put it on when the car will be unused 3+ days AND I won't be around. It takes me less than 10 minutes to get it out of the cellar, put it on my car and secure it but you're not going to want to take it off and put it on every day or even every other day. Just not worth it. Put a good coat of sealant or wax on the car and it will be sufficiently protected from the elements - rain, sun, etc. My detail process:
http://www.e90post.com/forums/showthread.php?t=667117
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2024 BMW M3 Sedan Frozen Pure Grey II/Fjord Blue, 6MT
Past: 2021 Z4 M40i Frozen Grey II/Black Alcantara | 2017 F30 340i Mineral Gray/Coral Red, 6MT | 2011 E92 335i Le Mans Blue/Black, 6MT