If your mister stops operating as it should the ceramic disk can be replaced. A "Key" tool is included with this replacement disk. If given proper care, each disk can last for thousands of hours. To prolong the life of each disk avoid touching the disk with anything at any time (particularly when in use). The safety switch will shut the unit off if the water is too low in order to avoid damage, but as an extra precaution it should always be unplugged before removing from water.