I have a Mercedes-Benz E220 Bluetec 2016 model, with 5,000-plus miles on the clock. I have been advised by Mercedes during the last service to replace both rear tyres as they have developed tiny cracks at random along the edge of the tyre, where the top of the tyre meets the side wall. I was also advised to replace the tyres every two to three years, regardless of the wear and tear, as 'they deteriorate with age'. The tyres on my car are Continental Conti Plus 255/35 R18 94Y.