Curious as to what mileage would be normal before brake rotors & calipers, brake pads & sensor should need to be replaced. Our GLC220D has only done 69000 kms & none of our previous Mercs & our heavy trucks have required replacement so soon - all have been well over the 100,000 km mark. Was shocked to even have to replace rear & front brake pads at this stage let alone brake rotors & calipers. Is this common??