Have never used covers. And my 10 yr old
25,000 mile Michelins have no weather cracking and still look new. And in Tx HOT summers including driving on trips in 105+ temps. We are sometimers and the Monte is stored under cover.
Note that due to my wife's mother's health we did not use the Monte at all last year and only once the year before. New tires going on before this season.