Ecovacs DEEBOT T30S

It empties into a 3 L bag and holds 4 L of clean and 3.5 L of dirty water, and it cleans its own base, so most homes go weeks between upkeep.

The robot is 4.1 inches tall, so it fits under taller furniture but may not clear very low sofas or cabinets.

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

It runs up to 290 minutes per charge, among the longest available, and recharges and resumes for very large floor plans.