All alcohol testers have a finite lifespan. Looking after them with regular calibration servicing on an annual basis helps to extend the sensor accuracy, however there will be a point at which the device stops holding the calibration settings and is deemed a calibration failure. Unfortunately ,sometimes the only time this is established is when the unit has been sent into us and is in the workshop undergoing its servicing. If this is the case, we will contact you to check how you would like to proceed and take all steps necessary to ensure a happy outcome – including offering a discount towards a replacement unit!