It depends on how often you use it, if you use it properly, and if you keep it clean and properly stored. When used properly, kept clean and stored dry, DMT diamond sharpeners will last a very long time. They do not last forever, but they last for several years.
If you use your sharpener as part of your daily work and use it many times a day, you will likely need to replace it in a few years after extraordinary service. If you use your sharpener to sharpen your kitchen knives every so often, chances are your sharpener will last ten or more years. Some of our customers report their DMT® sharpeners are still performing after twenty years of service!