Aspects of the present disclosure include a sensor configured to store in memory indications of sensor use information and formulas or indications of formulas for determining the useful life of a sensor from the indications of sensor use information. A monitor connected to the sensor monitors sensor use and stores indications of the use on sensor memory. The monitor and/or sensor compute the useful life of the sensor from the indications of use and the formulas. When the useful life of the sensor is reached, an indication is given to replace the sensor.