How often should I clean the dishwasher, and what product is recommended?

Maytag recommends using affresh® dishwasher and disposer cleaner once a month as part of routine maintenance to help avoid odor or odor-causing residue. Place one affresh® tablet in the main detergent tray and another in the prewash tray (or on the bottom of the dishwasher), then run the most aggressive cycle available. Use foil wrapper or gloves when handling the tablet. (Page 9)