Disclosed are methods and devices for varying functionality of a wearable computing device. An example device includes a first sensor and a second sensor. An example method includes, while a device is operating in a first state, receiving an indication of a touch input at the first sensor. The second sensor is configured in an idle mode based on the device operating in the first state. The method further includes, in response to receiving the indication of the touch input, triggering the second sensor to operate in an active mode and receiving data from the second sensor. The method further includes determining, based on the data, whether the device is being worn.