A lot of people who purchase a digital torque wrench believe that they are self-calibrating and that the calibration of the wrench doesn't need to be checked.
Nothing could be further from the truth.
When you turn on your digital torque wrench, it does a "self-check" (much like a late model motor vehicle when you start it up) to make sure the transducer and internal circuitry are ok, but it doesn't calibrate itself.
So digital torque wrenches need to have their calibration checked just like you would do with any other style of torque wrench (i.e. click type torque wrenches). This is the only way to tell if your digital torque wrench is compliant and to ensure that the torque value shown on the LCD display of the torque wrench is what the torque wrench is actually "pulling".
Digital torque wrenches do go out of calibration and are extremely sensitive to knocks and drops.
Don't be fooled by salesperson tech talk mumbo jumbo and remember that it doesn't matter if it is digital, the wrench still needs to be checked.