I was skeptical about robot vacuums. They seemed like a gadget people buy, use for two weeks, and then ignore while it collects dust in a corner — ironically. But after six months of running one every day in a two-bedroom apartment with a dog, I have a clear picture of what they are good at, what they are terrible at, and whether the money is worth it.

What it does well (surprisingly well)

The thing I did not expect: it changes how clean your floor feels. Not visually — a robot vacuum does not deep clean. But it picks up the invisible layer of dust, hair, and crumbs that accumulate every single day. Before the robot, I vacuumed once a week. By day four, there was dog hair in the corners and crumbs under the dining table. Now the floor feels barefoot-clean every morning because the robot runs while I am asleep.

The mapping feature on newer models (I have a mid-range model with LiDAR mapping) is not a gimmick. It learns your floor plan and cleans in straight lines instead of bouncing around randomly. It takes about 45 minutes to do 800 square feet. It returns to its dock and empties itself. I empty the base station bag about once a month.

What it is terrible at

• Cords on the floor. It will eat them. Phone chargers, lamp cords, laptop cables — anything loose on the floor will get tangled in the brush. I spent the first week robot-proofing my apartment by tucking cords behind furniture.
• High-pile rugs. My bathroom rug is too shaggy for it to climb onto. It tries, gets stuck, and sends me a notification. Medium-pile rugs are fine. Shag and high-pile are a no.
• Wet messes. If the dog knocks over its water bowl, the robot will spread the water into a thin film across the entire floor. Most models are not smart enough to detect liquid. You need to pick up before you run it.
• Corners. The round shape means it misses the very corner of every room. You still need to hit corners with a stick vacuum or broom once in a while.

Is it worth the money?

For me: yes. It saves me about an hour of vacuuming a week, which is 50 hours a year. The model I bought was around $350 on sale. That is $7 per hour of my time saved in the first year alone, and the thing will last several years. But if your home is mostly carpet and you have kids leaving toys everywhere, a robot vacuum will constantly get stuck and you will spend as much time rescuing it as you would just vacuuming normally.

They work best in homes with mostly hard floors, minimal clutter on the floor, and pets that shed. They work worst in cluttered homes with lots of cords, shag rugs, and kids’ toys scattered around. If your home is in the first category and you can get a mapping model on sale, I think it is worth it. If your home is in the second category, save your money and buy a good cordless stick vacuum instead.