Everyone has their opinion but IMO the sun is the worst enemy followed closely by ice / snow. My plan, cover in winter, park in as much shade as possible when not in use during the season (under hardwood trees) and always cover tires when not in use. I didn't cover them this year because I'm replacing them this spring. It only took us about 25 minutes to install cover this past fall but as others have pointed out, get it sized correctly and secured well. 55MPH winds last week and no issues with mine (knock on wood). That said, if I could afford it I'd have it under one of those big shelters.