Wearable devices have the potential to grow into a significant consumer market, benefiting from the ubiquity of the smartphone, and the growing self-health movement; but their success, of course, is not guaranteed. With sensor-laden wearable devices there are a unique set of challenges to be overcome. In this report, available to clients, we examine five major strategic challenges associated with key wearable devices and raise questions that will need to be addressed next year and beyond.