Usually changed every 2 years, old brake fluid can gradually cause corrosion over time as it absorbs moisture from the air. If you notice a spongy feeling in your brakes, or they feel less responsive than normal, then it could be a sign to change your fluid.
What is the DOT number?
The DOT number refers to the rating of the fluid. The higher the DOT number the better the rating, with DOT 4 brake fluid being the most common. For the best match for your vehicle check the plastic cap on your brake fluid reservoir, this will usually state the required dot level, or refer to your owner’s handbook.