Brake lining replacement is typically recommended when the brake linings have worn down to a certain thickness or level. This level can vary depending on the type of vehicle and the type of brake system it has.

Generally, it is recommended to replace brake pads when they have worn down to around 2-3 millimeters of thickness. However, it is always best to consult your vehicle's owner's manual or a certified mechanic to determine the specific recommendations for your vehicle.

Additionally, it's important to pay attention to the signs of worn brake linings, such as squeaking or grinding noises when braking, reduced braking performance, or a longer braking distance. If you experience any of these signs, it's important to have your brakes inspected as soon as possible to determine if the brake linings need to be replaced.