Robot vacuums are rightly famous for their ability to find their way around your home, avoiding obstacles such as furniture, loose shoes, and the like. But even with their optical sensors and ability (in pricier models) to map your home’s floor plan, even the best robot vacuums can find their way into situations they can’t get out of. That said, if you follow your robotic buddy during its first few forays around your house, you can generally identify the trouble spots and do something about them. My Roomba, for example, repeatedly got stuck when it rolled on top of a rubber doorstop and couldn’t roll back off. My solution: Pick the doorstop off the floor before starting a cleaning. I also noticed that the Roomba would stop dead in its tracks when it approached the stairway to our basement and detected the sudden drop. After some deliberation, I decided to block the doorway to the stairwell (which lacks an actual door) with a nearby bench. Of course, pricier robot vacuums that create their own floor plans can be programmed to avoid trouble spots, and there are also accessories (such as iRobot’s $60 Virtual Wall Barriers) that allow you to create a virtual fence that your robot won’t pass. But with a little ingenuity, you can come up with low-tech solutions that don’t cost extra.