Brake fluid should generally be changed every two years or every 24,000 miles, whichever comes first. This interval is recommended by most vehicle manufacturers to maintain optimal brake performance and safety, as brake fluid absorbs moisture over time, which can reduce its effectiveness and potentially damage the braking system

. Some sources note that depending on the vehicle make and model, driving conditions, and brake fluid quality, the interval might vary slightly. For example, some manufacturers recommend changing brake fluid every three years or up to 45,000 miles, while others suggest more frequent changes, such as annually during an MOT or service

. Signs that brake fluid needs to be changed include a spongy or soft brake pedal, delays in braking response, brake warning lights, or fluid discoloration (darkening to the color of coffee or cola). Regular checks of brake fluid level and condition are advised, ideally during routine oil changes

. Because brake fluid is hygroscopic (absorbs moisture) and toxic, it is recommended that brake fluid changes be performed by a professional mechanic to ensure the correct type is used and proper handling and disposal procedures are followed

. In summary:

• Change brake fluid every 2 years or 24,000 miles (whichever comes first) as a standard guideline.
• Check your vehicle’s owner manual for specific recommendations.
• Monitor brake pedal feel and brake fluid color for signs of degradation.
• Have brake fluid changed by a professional for safety and compliance.

This approach helps maintain braking efficiency and avoid costly repairs to the braking system