Tire Covers for 2013 Sprinter 3500

Have a 2013 LTV Unity TB Sprinter 3500 & wondering how many of you place Tire Covers on your wheels during the hot summer months? Our Sprinter sits in our driveway several weeks at a time with the sun hitting directly on them especially on the drivers side. The unit is in storage now but wondering if I buy a set of covers, what size do I buy & is it something we should consider to prevent sun damage? Any comments would be appreciated.
Don & Jean
2013 LTV Unity Sprinter 3500