PRODUCT AGE MONITORING DEVICE AND METHOD OF USE OF THE DEVICE

An age monitoring device 110 (105 in figure 1) for monitoring an extent of ageing of a product (100 in figure 1) includes: (i) an instrument 117 for measuring a value of a parameter which is a property of the product; (ii) a timer 113 for recording a time of use and/or non-use of the product; and (iii) a computing processor 111 operable to receive a signal from the instrument to indicate the measured value of the measured parameter and to receive time information from the timer and to calculate a cumulative extent of notional ageing of the product using a variable rate of notional ageing which has a predetermined dependence on the value of the measured parameter. Also is described a method of operation (200 in figure 3) of the age monitoring device. As specific parameters are mentioned temperature and shock.