Very frustrating. I bought one from REI for my wife. She followed directions, but the readings were all over the place. It would be working, then, it would be on zero. Even after our ride, just walking around, the readout was wrong. The strap was good and consistently tight. We called REI and they asked that we come in and switch for another one; watch and strap. Same problem with the second one.
Based on your experience, is this unusual?