A pigment such as crystal violet is impregnated in or otherwise affixed to a translucent plastic or porous member (14, 22). The color change material changes at least one of opacity or color with repeated exposure to a fluid sterilant, such as an oxidant solution. A label (10, 24) is mounted behind the translucent plastic material and carries an indicia (12, 26). With repeated sterilizations of the instrument, the color change material becomes progressively more translucent, allowing the indicia to be read through the translucent plastic material. When the indicia becomes visible, such as after about 7 sterilization cycles in FIG. 3, the user is warned to discontinue use of the instrument, either discarding it or having it rebuilt. Rather than having a written indicia, a color scale (30) can be provided for comparison against the current color of the color change material. When the color changes to the discard color on the color scale, the user is again advised to discontinue use of or rebuild the instrument.