Yes, it can and here's the proof! This photo was taken of a BACtrack S80 that was sent to BACtrack's Calibration Lab by a customer:
BACtrack calibration technicians serviced the breathalyzer, re-calibrated it, and sent it back to the customer the very same day.
While this is an unusually high test count, it is proof that a regularly used BACtrack really can remain accurate over very intense testing periods.
BACtrack recommends calibration service once a year, but it is not required. Using your BACtrack regularly will actually help to maintain performance and accuracy, as moisture in the breath helps the performance of the sensor.