This is a truly awesome machine. We have one cat and the granules need replenishing at least once per month. The waste of granules is partly from the cat tracking them out of the box. We placed a litterbox rug in front of the Catgenie and that helps catch a lot of the granules so they don't track around the house. Those litterbox rugs are available at any pet store. This is still far less work than an ordinary litter box, and far more sanitary, fresh-smelling and attractive.