Properly maintained and used, the KitchenAid Mixer should provide a lifetime of mixing fun! But that doesn’t mean you won’t have to change the grease or have new brushes fitted. Adjusting the tilt-head height is also a routine that needs to be done from time to time. But it’s main damage caused to mixers of all varieties is the foreign objects like spatulas being dropped in the bowl during mixing. This normally damages the worm gear and will need replacing.