when color of brake,transmisson,power st fluids turn dark

Brake fluid should be clear to amber in color, it absorbs moisture from the air over time which is harmful to the brake system and turns dark over time due to moisture and contamination. Automatic transmission oil should be red starting out but has high detergent characteristics and turns brown as it ages. Power steering has the identical color and characteristics as transmission fluid. I am a believer in changing fluids periodically and have seen our customers cars last 200k, 300k and 400k miles due to frequent engine oil changes and other periodic fluid changes.