Dreame D30 Ultra

It empties into a 3.2 L bag and holds 4.5 L of clean and 4 L of dirty water, so most homes go weeks between refills, and the dock cleans its own base.

The robot is 3.8 inches tall, so it slides under most sofas and cabinets, though very low furniture may be tight.

It clears obstacles up to 20 mm, so it handles standard door sills but may stop at taller thresholds.

It covers about 1,679 sq ft on a 230-minute charge, and recharges and resumes to finish larger homes.