I have owned my machine for many years. I recently sent two machines to my daughter; she has lots of cats. At one time, I had six cats and half of them used the machine; the others insisted on regular boxes. I currently have two cats (MUCH EASIER) and neither of them is impressed with the machine. I notice rarely they DO use it; I hear the machine cleaning itself. I would dearly love to convert them full time to the robot. Any suggestions?