This thing is awesome on hardwood floors or tiles. It finds all the dirt, and is so smart! It handles obstacles with ease. I have not had a huge success on carpet, and if it gets too extended from home base, it can get lost, and you have to pick it up and help it. It's like a cat. It does amazing things, but you need to reach down and pet it from time to time. If my cat won't let me work at my computer, turn on the robot, she runs upstairs. Problem solved. If you have a cat, you MUST get this robot. It finds all the hair and tracked litter bits.