Battery life, noise, height, and boundary markers: These can all be moderately important, depending on your home and expectations. An hour of battery life is fine, but longer run times are never a bad thing, especially for bump-and-run bots. Quieter bots are always better—some are as quiet as 54 dBc, so you won’t have to raise your voice or turn up the TV to hear over the bot. Some bots are louder than 65 or even 70 dBc, which is noisy enough that it’ll probably become uncomfortable to be near after 20 minutes or so. But if you’re usually out of the house (or on a different floor) while yours runs, it doesn’t really matter. Shorter bots get under more furniture, but that only matters if you have furniture that sits low to the ground in the first place. Boundary markers are obsolete if you get a bot with smart mapping but can still be useful with other models. Roomba’s invisible wall system is much more elegant than the magnetic strips that most other brands rely on.

Bot shape, extra cleaning modes, dustbin size: These are usually pretty unimportant. D-shaped robots are better at cleaning corners than round robots, but the round bots have side brushes that usually get the job done anyway. Spot cleaning (common) and manual steering (less common) can be handy sometimes. But most people use the automatic, whole-house option almost all of the time and rarely bother with any others. A bigger bin might be handy if you have a lot of sheddy pets (or people) in your house, but usually it doesn’t matter, and the size differences aren’t all that substantial anyway.