As a technical support representative for a large safety equipment distributor, I take calls every day from people asking about one of our many direct-read gas detectors, or “gas monitors.” All of these callers want to do the right thing: protect their employees from potentially dangerous environments. What’s surprising, however, is the reluctance to buy calibration equipment for the instrument they are purchasing. The usual response is, “Aren’t the instruments already calibrated from the factory?” Of course they are. But, without verifying the function of the sensors with a bump test before each use and calibration on a regular basis, end-users cannot be certain the reading displayed is accurate and the alarms are functioning properly.