When is a good time to have a logger re-calibrated?   This is a question that will cross the minds of everyone responsable for managing an inventory of loggers.

Once every twelve months is a standard time period between calibrations.

The most common reason for a logger to go out of calibration is unintentional handling mishaps to a logger. i.e. any handling incidents suffered by a logger that are out of your control for instance while a logger is in transit with a product shipment etc.

As an example if a logger has been dropped on to the floor there is a chance that the temperature sensor has had stress applied to it from the fall.  If this has happened the stress applied to the loggers temperature sensor will change the characteristics of the temperature sensor which can change the accuracy of the logger. This event could shift the logger accuracy away from results provided on the original calibration certificate. For this reason alone it is good practice to have your loggers accuracy checked annually by re-calibration.