It's been said that the brake hoses start delaminating internally, restricting fluid flow when the pedal is released, which would eat the pads faster than normal. The hoses should be replaced at least every 10 years as preventive maintenance, and the fluid must be flushed every 2 years per MB specs. I'd start with 4 new hoses ($9 each) and pressure bleeding with fresh DOT4+ fluid, and pop in the aforementioned Textar pads - I bet that cures it. You probably need to do the fluid flush anyway!
Regards,