iRobot Roomba Plus 507 Combo

How the mop is built: flat pads, two spinning discs or a roller. Discs press harder on dried-on dirt, a roller rinses itself while it works.

The pad slides out along a wall or a kickboard, so the last few centimetres are mopped as well.

The dock empties the robot’s dust bin, usually after every run. You only empty the dock’s bag or bin.

The dock collects dust in a bin instead of a disposable bag. No bags to buy, but you empty it yourself.

How long the maker says a dust bag lasts with daily use. With pets or a lot of carpet it is shorter.

The dock washes the mop for you, so you do not rinse it by hand.

The dock dries the mop afterwards, so it does not sit there wet and start to smell.

Drying is done with warm air instead of cold. It is faster and it helps against smell.

How the robot maps your home and follows that map. Lidar measures with a laser and works in the dark, a camera looks along and recognises more.

How the robot sees loose things on the floor, such as cables, socks or a pet accident. A camera with depth sensing sees more than a bumper that reacts on contact.

How tall the robot is. It decides whether it fits under your sofa, bed or cabinet.

What the robot weighs. It counts most if you carry it up a staircase every day.

Matter is the standard that lets devices from different makers work together. With it you can run the robot outside the maker’s own app.

Which voice assistants the robot works with, such as Google Assistant or Alexa.