An electronic tag (8) displays and monitors a maintenance state of an associated electrically-powered device. The tag includes data storage (2) for storing data indicative of the maintenance state, the data comprising information defining an expiry date for the maintenance state. A data processing unit (3) monitors a remaining duration to the expiry date and a display (4) displays information indicative of the maintenance state. A cut-out unit (7) controllably enables transmission of electrical power to the associated electrically powered device dependent on the remaining duration.