Aspects of automatically determining a period of time when a wearable electronic device is not being worn are discussed herein. For example, in one aspect, an embodiment may automatically determine a period of time when the wearable electronic device is not being worn based on a comparison of the motion data and a not-worn profile that specifies a pattern of motion data that is indicative of when the wearable electronic device is not being worn by a user. The wearable electronic device also stores in the non-transitory machine readable storage medium, data associating the period of time with a not-worn state.
