I went to a brake seminar held by a Mercedes dealer in Minnesota and there were a couple of things that I remember.

1st, if the car has ABS, the brakes should be bled with a pressure of around 29 pounds. This requires a pressure bleeder.

2nd, when the dealership stopped using the old two man, pump the brakes approach to bleeding brakes, they no longer had to replace master cylinders. In other words, almost all the master cylinder problems they had they caused themselves by pushing past the normal wear point in the master cylinder.