1. Brake fluid is ‘hygroscopic’ (a technical term for absorbing moisture) which can lead to brake failure if not properly maintained.
2. As brake fluid ages it can become contaminated with small particles, which causes the boiling point of the fluid to decrease, reducing braking efficiency.
3. The braking process generates a lot of heat, which breaks down and wears away at your brake fluid. Again, this leads to your braking efficiency to be reduced.

Manufacturers recommend a brake fluid change 3 years from new and then every 24 months or 20,000 miles thereafter.

It is as vital to stopping a vehicle as engine oil is to keeping it going.