dealer just did brake flush on my Z4. I thought it was excessive on a car with only 1000 miles on it. the dealer said it has 2 be done every 2 years regardless of mileage. It was covered under warranty so I figured what the hell do it. I have had cars that were over 10 years old 100,000 miles on them that never got flushed except for a little when bleeding after brake job ,never a problem.
Given the price of BMW parts and the fact we a talking about maybe $10 in brake fluid and how simple it is to bleed brakes I Will continue to do it even after the warranty ends