Hello,

from our suppliers we have a guarantee of 6 months for our pH and Redox sensors. Usually, after a sensor has been used 6 to 9 months in a tank, the performance decreases. If you increase the calibration tolerance or/and clean the sensor, their durability can be extended.
If a sensor is not used in a tank but only stored, then of course the durability is longer than the 6 months...

For an oxygen sensor, the durability is much longer. When they are regularly cleaned, it can be up to 2 - 4 years.