Q&A

 Master

Brake fluid absorbs moisture from the air naturally. This moisture then in the brake fluid can cause rust and contamination in the brake fluid and lower the boiling point of the brake fluid. Brake fluid new is clear in color, brake fluid over time turns dark when it absorbs moisture and contaminants so I am a proponent of flushing the brake fluid particularly on cars with ABS brakes and in areas of the country where there is lots or moisture (rain, snow and or humidity).
Power steering fluid flushes on cars with known problematic steering components I would say yes flush the fluid periodically every 30,000 miles or if it smells burned (Acura use a special fluid). Transmission fluid drain and refill every 30,000 miles would be advisable but using the machines that flush fluid trough the transmission I have read about it causing sludge to dislodge and cause trouble occasionally on a transmission that had previously not show signs of problems.
All depend on your long term goals for your car. I believe in prevention rather than cure, many of our customers commute to work and have 200,000, 300,000 and one customer had 464,000 on the one engine.
There is a fine line to draw between selling preventive maintenance and "over selling work".