A package in which a medical device is stored, the package comprising an outer shell providing a vapor barrier, a medical device positioned in the interior space inside the outer shell, the medical device including a liquid-containing element that is subject to drying out, a condition sensor comprising two metallic elements and a conductive water-containing element, each of the two metallic elements being composed of different metals, with each of the different metals selected so that the two metallic elements form an anode and a cathode of an electrochemical cell, so that the water-containing element forms the electrolyte of the electrochemical cell, and the voltage of the cell provides an indication the conductive water-containing element of the medical device has dried out.