Brake Fluid Flushes
Bavarian Professionals and BMW recommend brake fluid flushes every two years, regardless of mileage. Brake fluid is hygroscopic, which means that it naturally draws in water from the atmosphere, which in turn poses a few issues for your brake system. Brake fluid boils at ~450 degrees Fahrenheit, while water boils at 212 degrees. Due to the heat generated under braking, any water in your brake fluid can boil, which in turn will cause the braking system to not perform properly. Water is also compressible, and the relative incompressibility of brake fluid is what gives a normal, firm pedal feel. Finally, brake fluid also serves to prevent corrosion in the lines and fittings of the brake system, which the presence of water instead causes.