Under normal circumstances, how much wear does the brake pads need to be replaced?

Now new cars should have brake pad wear sensing wires. One end of the sensing wire is inserted into the brake pads. As long as the brake pads are worn to the set life, they will touch the wear sensing wire and the dashboard will light up. At this time, the brake pads should be replaced immediately.

Generally, the brake pads of most current models have a metal sheet similar to the one shown in the photo below. It is generally called a wear alarm. When the brake pads are worn to the position of the alarm, the alarm and the brake disc are in contact with each other. A sharper noise occurs, which means that the brake pads should be replaced. More high-end models have electronic sensors. When the sensor is worn to a certain position, the sensor will be disconnected, and the dashboard will prompt the brake pad to be replaced.