Hello, we got a used Toyota Yaris in 2011 (built in 2007) with 65,000 km. There were summer tires from Michelin (DOT 2009). These are alternating with the winter tires on the car, which has now reached 135,000 km. We want to drive the car for a few more years… now the questions about the summer tires: – profile approx. 2.5-3 mm (uniformly driven off) – slightly porous at the transition outside -> running surface The next years the car will be “degraded” to the second car and if we invest something, then best now (Tüv is new- car had on it at the Tüv time but winter tyres from 2015 are on, oil and brake fluid changes are on). Father-in-law thinks renewal is unnecessary, because enough profile and tires are not yet old… Objective information is hard to find on the Internet, except that 1.6mm are the minimum. How do you see this?