The brushes in the AT Series Brush drivers wear during use and the rate of wear is dependent on factors such as torque setting, speed, and how many times the driver is activated. If a driver is used at top speed, set for the middle of its torque range, and is triggered for 0.5 seconds with a 3.5 second pause between each trigger, the brushes would last approximately 2,000,000 cycles, or about 8,000 cycles per day in one year.