A wearable infusion device delivers a liquid medicant to a patient. The infusion device comprises a base that contacts a patient's skin and a reservoir arranged to be filled with a liquid medicant to be delivered beneath a patient's skin. The reservoir has an outlet through which the medicant flows. The infusion device further comprises a flexible conduit communicating with the outlet of the reservoir, a pump that causes the medicant to flow down the conduit, an actuator that performs a function related to the operation of the device, and an enable mechanism that enables the actuator in response to the filling of the reservoir with the liquid medicant.