A method for predicting the usability of a relay or a contactor is described herein. A current flowing through the relay or the contactor and/or a voltage applied to the relay or the contactor is measured repeatedly, and the measured values are transmitted to an observation unit. The observation unit makes a prediction relating to the usability of the relay or of the contactor on the basis of the measured values and a model. Furthermore described are an observation unit and a battery which are configured to carry out the method according to the disclosure.