We do not have lifetime characterized for the DRV8825 stepper motor driver or our stepper motors. However, some of our customers have used them in commercial designs and industrial settings, and we have not heard of them having issues.
The stepper motor driver board is just a carrier board for the DRV8825 stepper motor driver IC, and all the information we have for the IC is from its datasheet. If you have questions that aren't covered by the datasheet, you might try contacting the manufacturer for additional information. The datasheets for our stepper motors are also available, but do not contain information about their lifetime, so you might try contacting the manufacturer for the steppers motor as well.