How often is everyone changing brake fluid?

 

By the book its every 20K or every year.
I did at 20K and 40K.
Right now Im close to 60K and planning to do it at 70K.
All what I found online telling me it can be done every 40K. But Im not a super tech

 

My dealer does it every two years - according to the maintenance manual.

 

+1 (I agree with heida11, every two years)

 

Every two years.

 

Brake fluid attracts water from the atmosphere over time, even in a sort of sealed system small leaks permit this. The impurities reduce its temperature tolerance and that can impact function under extreme conditions when brakes could be most critical.
It's time, not mileage, that matters.
Now, that said, consider a random sampling of average drivers and I bet only those who don't lease but actually own high end brands even consciously know to change it, and that over 90% of the cars we drive by daily have original factory fluid...