The case for a dock is not that you never touch dust. It is that a small bin fills before the robot finishes the room, and a shedding animal fills it faster than any brochure assumes.
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On-board bins are small. Where makers publish the figure it is a fraction of a liter — ECOVACS states 0.22L, Dreame states 395ml. In a house with a heavy shedder either fills within a run or two, and a full bin means the robot stops mid-floor. That, not convenience, is the argument for a dock.
Self-emptying is sold as a luxury: never touch the dust. That framing is why people talk themselves out of it. The practical case is much more boring and much stronger.
The capacity numbers, where they exist
On-board dustbin capacity, where the manufacturer publishes it
2 of 6 models publish this figure. Every number below links to the page it came from.
Compiled from the manufacturers’ own published material on 2026-09-01. We have not measured any of these figures ourselves — see how we pick. Found an error? Tell us and we will correct it.
Almost nobody publishes this. Two of the models we cover state a capacity; the rest do not mention it on the pages we could read. That is a shame, because it is one of the few specs in this category that is directly comparable between brands — a liter is a liter regardless of who measured it, unlike a pascal.
What a shedding animal does to those numbers
Hair is bulky and light. It occupies bin volume out of all proportion to its weight, and it does not compact the way dust does — it forms a springy mass that blocks the intake before the bin is technically full. The practical consequence in a house with a shedding dog is that the usable capacity is well under the stated one, and the robot's full-bin behavior arrives sooner than the numbers suggest.
So halve any interval you are quoted. A dock advertised at 60 days is a realistic month in a shedding house, and one advertised at 100 days on a 3.2L bag is a couple of months. That is still a very different life from emptying a 0.4L bin by hand every day or two.
What you give up with a dock
Floor space. A full station is a piece of furniture, not an accessory, and it needs a wall with clearance on both sides and in front.
Bag cost. Bagged docks are consumables. Bagless self-empty bases exist — Shark's Matrix Plus uses one — and trade the running cost for a dust cloud when you empty them, which matters if the reason you bought it was allergies.
Noise. The empty cycle is loud, for about ten seconds, and it happens whenever the robot returns. Schedule around anyone who works from home.
What each dock does, and the interval each maker claims
23 of 23 models publish this figure. Every number below links to the page it came from.
Compiled from the manufacturers’ own published material on 2026-09-01. We have not measured any of these figures ourselves — see how we pick. Found an error? Tell us and we will correct it.
When a manual bin is the right call
One or two rooms, no shedding animal, and hard floors: a manual bin is fine and you have saved a real amount of money and floor space. The robot will finish the floor on one bin, and emptying it takes ten seconds. The dock earns its keep specifically where volume is the constraint — carpet, animals, and a whole floor to cover.
Quick picks
Ranked on the published specifications below. Tap a row to jump to the full write-up.
#
Product
Best for
Main brush
Price
1
RoborockNo photo
Roborock Qrevo CurvPublishes both a standard-threshold and a double-layer threshold figure, which is the number most sill-blocked buyers are actually shopping for.
Dreame X50 UltraThe only model here that legs itself over a step rather than driving at it, and the only one that publishes the condition attached to its own headline number.
40mm (1.6in) double-layer, 30mm (1.2in) standardRoborock's own wording is that it can overcome standard thresholds up to 3cm and navigate double-layer thresholds up to 4cm. Stated maxima assume a clean square edge; a rounded or worn sill behaves differently.Source: Roborock Qrevo Curv product page — threshold crossing (retrieved 2026-09-01)
The only model here that legs itself over a step rather than driving at it, and the only one that publishes the condition attached to its own headline number.
60mm over a series of steps, 42mm over a single stepDreame's own condition, quoted: "The gap between steps should be greater than 4cm. For a single obstacle crossing and a single vertical step, the highest obstacle crossing height is 4.2cm." The 6cm headline therefore does not describe a single door sill.Source: Dreame X50 Ultra product page — ProLeap step climbing (retrieved 2026-09-01)
Publishes the caveat as well as the headline, which is rarer than it should be
20,000 Pa stated peak suction and a 395ml on-board bin
Stated 220 minutes of runtime in quiet mode
What it does not
The legs add height and mechanical complexity to a machine that lives under furniture
10.5mm mop raise is modest next to the 17mm figures from Roborock
Who it is for
Split-level rooms, a sunken living room, or a doorway sill that has beaten every robot you have owned.
Skip it if
You read the 6cm headline and stopped there. Dreame's own footnote puts a single vertical step at 42mm, and 6cm only applies to a series of steps with more than 4cm between them.
In a house with a shedding animal or a lot of carpet, yes — the on-board bin is the limiting factor on whether the robot finishes the floor. In a small hard-floor home without pets it is a genuine luxury and you can skip it.
+ How often do you actually empty a self-emptying dock?
Manufacturers quote 60 to 100 days. Halve that for a heavy shedder. The real signal is the robot's own behavior: if it starts reporting a full bin more often, the dock bag is close.
+ Bagged or bagless self-empty base?
Bagged for allergies, because the dust stays sealed when you change it. Bagless if running cost matters more than dust exposure. Bagless bases also need occasional cleaning inside, which bagged ones largely do not.
+ How big is a robot vacuum dustbin?
Where it is published at all, a fraction of a liter — ECOVACS states 0.22L on the X8 Pro Omni and Dreame states 395ml on the X50 Ultra. Most makers do not publish the figure, which is why the table above has gaps.
