[quote=othomasjr]What would happen if you didn't have it done? QUOTE]
You could find yourself suddenly without effective brakes. Do flush the brake fluid regularly. Brake fluid is hygroscopic and the absorbed moisture is fairly compressible plus, when heated, it creates vapor, which is even more compressible. All of this is before corrosion sets in.
Brakes are funny that way, they fail at the worst possible time.