18. What are the optimal storage conditions for sensors?
[...] Oxygen sensors are a special case since their life is consumed when they are put on load. For this reason they are either shipped off-load or in sealed packages where the oxygen level is held at a reduced level.
31. How do I know when to replace my sensor?
[...] Oxygen CiTiceLs however have a finite life; the length of their operating life will be determined by the total exposure to Oxygen. This is because the sensor has a metal anode which is consumed by the reaction mechanism. The characteristic of Oxygen CiTiceLs is that they have a stable signal output, which experiences minimal decline, right up until the end of the sensors life. At the end of the sensor's operating life there is a sudden and rapid drop-off in output as the sensor's anode is finally consumed.