That sounds like many of the drivers that I see in So. California.
(1) They don't know enough to leave sufficient room between cars, so that they have to keep using their brakes.
(2) They don't use a lower gear to go down hills.
(3) They drive with both feet on the pedals; one on the gas and one on the brake pedal (usually while talking on a cell phone).
Mercedes brake pads are fairly soft, so that they can wear out fairly quickly if you do most of the above. On e other hand, if you drive with a little inteligence, they can last several times 12,000 miles.
1972 220D 138k miles (sold)
1982 300SD 263k miles
1989 BMW 750iL 183k miles
1993 Dodge D250 Cummins 5.9 202k Miles