Abstract: An electronic tag is fixed on to a mechanical or electronic item or system, the electronic tag comprising at least one sensor such as an accelerometer to monitor the load in the item, a calculating means to receive signals from each sensor and to calculate the resulting damage to the item or to any other item attached to it, a memory to record data representing the resulting damage, and means to enable the recorded data to be downloaded. The tag calculates the damage caused by the accumulated vibrations and fluctuating loads that the item has been subjected to over its entire life (since the tag was attached), and this information remains stored in the tag even if the item itself is removed, stored, or used again.