Why must you ensure the brake fluid is changed regularly in accordance with the vehicle manufacturer's instructions?

Your answer is completely correct. In Germany, it is important to change brake fluid regularly for several reasons. First, the braking system must remain functional even under high stress, such as during long or steep descents where brakes are used intensively. Over time, brake fluid can absorb moisture from the air, increasing its water content. This moisture lowers the boiling point of the fluid, which can lead to vapor formation inside the brake lines and cause brake failure. Additionally, the water content can cause corrosion and damage to the braking system components like brake lines and cylinders. Following the manufacturer's recommended maintenance intervals ensures the brake fluid maintains its proper properties, keeping the braking system safe and reliable.