It should take about 50,000 miles (more or less) for the thickness to 3 to 4 millimeters. It all depends on how aggressively and frequently you use your brakes so while 50k miles is average for many, 20k miles may be more realistic for some. Also, keep in mind that some brake pad materials last longer than others.18 May 2020
They absolutely need to be changed if the discs are unevenly worn or badly scored. The points that are circled in RED are only points that the brake pad is in contact with the braking surface of the brake disc.
A Mercedes-Benz C-Class will cost about $10,734 for maintenance and repairs during its first 10 years of service. This beats the industry average for luxury sedan models by $970. There is also a 31.57% chance that a C-Class will require a major repair during that time.