Agree with others here.
The brakes themselves will not get hot in traffic , no matter how heavy , it is much more likely that they will be cool due to lack of use.
The fluid is critical , it is cheap , and can easily be changed. Much better to build this into an maintenance schedule if you do the work yourself , or get the service agent to do it every 2 years.
The only exception are race cars where it is changed much more frequently.
