Digital Precision Scale (20g Max / 0.001g Resolution)

Calibrating often might be a good idea. I've noticed the drifting upwards mentioned here - right after calibration, it usually measures the weight right (10.000 mg, or 1 mg up or down), but it starts slowly driving the measurement upwards after a while. So, trust the first reading. (And always do multiple measurements if you need high confidence)
Recently, the software developed a flaw - the Off button stopped working. However, when I press and hold the On button for a moment, it usually powers off. It did this occasionally before (holding On is supposed to take you into calibration mode). I can still calibrate though - if I hold On right after turning the scale on, it still (usually) takes me into calibration.