According to certain aspects of the disclosure, an uninterruptible power supply is provided comprising an input, a backup power supply, an output configured to provide output power from the input and/or the backup power supply, a sensor, a relay, and a controller coupled to the sensor and the relay and being configured to determine, based on stored relay specifications, a manufacturer total estimated relay lifetime, receive operational information indicative of operational parameters of operation of the relay from the sensor, the operational information including a current conducted by the relay, determine, based on the operational information, an effective number of relay cycles consumed by the operation of the relay, determine a modified number of remaining relay cycles based on a difference between the manufacturer total estimated lifetime and the effective number of relay cycles consumed, and output remaining relay lifetime information indicative of the modified number of remaining relay cycles.