You shouldn’t have to replace a coffee grinder often. If the grinder is well maintained, the grinder itself can last years. If you start to notice the flavor of your coffee change, or the speed of the grinder, it might mean you need to clean your machine or replace your burrs.  Burrs are often available directly from the manufacturer, and YouTube has some great tutorials on replacing them yourself. They’re also a lot cheaper than a brand-new grinder.  But fear not. Unless you grind multiple pounds of coffee daily, you should not worry about burr replacement more than once a year.