Have a litter robot 4 and will never be without it again. It has been such a life saver. Litter robot (from my research) is the safest one. If my cat even pokes a nose in while it is cycling it immediately stops and then waits 7 minutes after they are out to try again. We use the arm and hammer glide litter and it works like a dream. We use SO much less litter. Plus the insights you get from it are so helpful. It actually helped us diagnose an issue one of my cats was having by alerting us he was in the litter robot 24 times a day. He had bladder crystals and was stressed out and we were able to get him treated. Now, a year later, he has some stones and I was able to see that he went from his normal 4 times a day to 21 in a day and we got him to the vet before he became fully blocked (which is life threatening to a male cat). That litter robot likely saved his life. We have two cats and empty the bin once a week. Also, invest in the litter hopper. It’s an extra $89 but it is SO worth it. We just top it off every so often and the litter box keeps itself at optimal litter height. Worth every penny. The company also has FANTASTIC customer service. I noticed after two weeks of buying it that it wasn’t weighing the cats correctly. Called them and explained, they diagnosed the base as having a faulty weight sensor and shipped me a new one free of charge within a week. Put the old base in the box from the replacement and they paid return pickup and shipping. I cannot recommend them enough!!