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Bristle & Bot
Troubleshooting / comparison

Replacement parts and what they actually cost you

Brushes, filters, pads, bags and side brushes. Which ones wear, how to tell, and the design choices that reduce how often you buy them.

By Scooter M.Published
An assortment of small spare parts laid out on a table

Disclosure — some links on this page go to Amazon, and we earn a commission if you buy through them. It costs you nothing extra and it does not change what we recommend or in what order. The full disclosure.

Five things wear out: the main brush, the side brush, the filter, mop pads and dock bags. Replace them on behavior, not on a calendar reminder. An anti-tangle main brush and a bagless base each cut the annual bill, and the second costs you dust exposure when you empty it.

Running cost is genuinely different between models and it appears in no buying guide. Two robots at the same price can differ by a meaningful amount per year once you count bags, pads and brushes — and the difference comes from design decisions you can see before you buy.

What wears, and how to tell

The five consumables
PartThe honest replacement signalWhat reduces how often
Main brushFins gone soft and rounded, or a permanent flat spot. Not a calendar reminderAn anti-tangle design, because hair wrapping is what wears the bearings
Side brushArms splayed outward and no longer sweeping into the intake pathAnti-tangle side brushes; slower side-brush speed on hard floors
FilterStill looks gray after tapping it out, or airflow is visibly reducedEmptying the bin before it is full; a dock that seals
Mop padsComes out of the wash still stained, or the fibers have matted flatA dock that washes in hot water and dries the pad
Dock bagsFull. This one genuinely is a capacity questionA bagless base — cheaper to run, worse for allergies

These are behavioral signals rather than intervals. Manufacturers publish suggested intervals in each manual; where a machine is used harder than average — pets, litter, deep carpet — the behavior arrives well before the calendar does.

The design choices that lower the bill

  • An anti-tangle main brush. Hair wrapping the axle is what kills bearings, so a design that keeps hair off the axle extends brush life as well as saving you the weekly scissors. See rubber versus bristle.
  • A bagless self-empty base. No bags to buy, ever. The cost is a dust cloud when you empty it, which is a bad trade in an allergic household — see allergies and HEPA.
  • Hot-water pad washing and heated drying. Pads that are properly washed and dried last much longer than pads that are rinsed cold and left damp, which is the same reason those docks stop the mop smelling.
  • A washable filter, where the manual says the filter is washable. Some are and some are not, and washing one that is not destroys it.

Genuine parts or third-party?

For filters and mop pads, reputable third-party equivalents are generally fine and considerably cheaper. For the main brush, fit is what matters — a slightly wrong roller sits at the wrong height and either does not touch the floor or drags. For batteries, buy the manufacturer's pack; that is the one where a bad substitute is a safety issue rather than an inconvenience.

Before you replace anything

Run the ten-minute maintenance pass first. A large share of parts bought to fix poor pickup were bought to fix a brush that only needed clearing, or a filter that only needed tapping out. Cleaning is free; parts are not.

Quick picks

Ranked on the published specifications below. Tap a row to jump to the full write-up.

#ProductBest forDockPrice
1
Roborock Q7 M5Proper 360-degree LiDAR mapping and an anti-tangle main brush at a price where a lot of robots still bounce off the walls.
Real LiDAR mapping at the low endSelf-emptying dock, stated at seven to nine weeks
2
eufy X10 Pro Omnieufy publishes an obstacle clearance, a mop lift, two runtimes and both tank capacities — more of its own numbers than any other maker here.
The most completely published spec sheetSelf-emptying with auto mop washing and drying, 3L self-refilling tank
3
iRobot Roomba Combo j9+The mop arm retracts to the top of the robot rather than lifting a few millimeters, so it can mop and vacuum in one pass without routing around rugs.
Mopping without avoiding the carpetMulti-functional base that empties the bin and refills the mop tank, stated at up to 60 days

Every figure in this table is linked to the page it came from in the write-ups below. We have not tested any of these machines.

Top pick

Roborock Q7 M5

Real LiDAR mapping at the low end

Proper 360-degree LiDAR mapping and an anti-tangle main brush at a price where a lot of robots still bounce off the walls.

Published specifications

Stated suction
10,000 PaRoborock states this for Max+ mode.Source: Roborock Q7 M5 product page — "10,000 Pa HyperForce Suction" (retrieved 2026-09-01)
Max climb height
Not publishedNot stated on the Roborock product page.
Mop lift
Not publishedNot stated on the Roborock product page.
Main brush
JawScrapers Comb anti-tangle main brushRoborock pairs it with an anti-tangle side brush as a Dual Anti-Tangle System.Source: Roborock Q7 M5 product page — brush (retrieved 2026-09-01)
Navigation
360-degree LiDAR with multi-level mappingSource: Roborock Q7 M5 product page — navigation (retrieved 2026-09-01)
Stated runtime
Not publishedNot stated on the Roborock product page.
Dock
Self-emptying dock, stated at seven to nine weeksSource: Roborock Q7 M5 self-empty interval — manufacturer listing on Amazon.com (retrieved 2026-09-01)

What it does well

  • 360-degree LiDAR at entry-level money, so it maps rooms instead of guessing
  • JawScrapers Comb anti-tangle main brush
  • Multi-level mapping for a two-story house

What it does not

  • No published climb height and no published mop lift
  • Mopping is three water-flow levels and a pad, not a washing dock

Who it is for

A first mapped robot for a normal house — several rooms, some rugs, a pet.

Skip it if

You want serious mopping. This drags a pad; it does not wash or lift one properly.

Check price on Amazon

#ad how we are funded · no live price right now, so we show none

Full Roborock Q7 M5 write-up

Pick 2

eufy X10 Pro Omni

The most completely published spec sheet

eufy publishes an obstacle clearance, a mop lift, two runtimes and both tank capacities — more of its own numbers than any other maker here.

Published specifications

Stated suction
8,000 PaSource: eufy X10 Pro Omni product page — "8,000 Pa Suction" (retrieved 2026-09-01)
Max climb height
21mm (0.83in)eufy publishes this as "Obstacle Clearance Height". Like every stated maximum it assumes a clean square edge.Source: eufy X10 Pro Omni product page — obstacle clearance height (retrieved 2026-09-01)
Mop lift
12mmAuto-lifting on carpet detection.Source: eufy X10 Pro Omni product page — auto-lifting mop (retrieved 2026-09-01)
Main brush
Auto-detangling roller brush with Pro-Detangle CombSource: eufy X10 Pro Omni product page — brush (retrieved 2026-09-01)
Navigation
iPath Laser Navigation with AI.Map 2.0Source: eufy X10 Pro Omni product page — navigation (retrieved 2026-09-01)
Stated runtime
173 minutes vacuuming, 136 minutes vacuuming and moppingeufy states both figures for standard mode.Source: eufy X10 Pro Omni product page — runtime (retrieved 2026-09-01)
Body height
Needs 130mm (5.12in) of clearance under furnitureeufy publishes this as a minimum height restriction rather than a body height.Source: eufy X10 Pro Omni product page — height restrictions (retrieved 2026-09-01)
Dock
Self-emptying with auto mop washing and drying, 3L self-refilling tankThe robot itself carries an 80ml water tank.Source: eufy X10 Pro Omni product page — station and tanks (retrieved 2026-09-01)

What it does well

  • Publishes an obstacle clearance figure at all, which iRobot and Shark do not
  • 12mm auto-lifting mop with carpet detection
  • Separate stated runtimes for vacuum-only and vacuum-plus-mop

What it does not

  • 21mm clearance is mid-pack and well below the Curv or the L40s
  • 8,000 Pa is modest against the current flagship figures

Who it is for

Anyone who wants to check the specs before buying rather than after the robot arrives.

Skip it if

Your sills are over about 20mm. A published 21mm clearance is honest, but it is not tall.

Check price on Amazon

#ad how we are funded · no live price right now, so we show none

Full eufy X10 Pro Omni write-up

Pick 3

iRobot Roomba Combo j9+

Mopping without avoiding the carpet

The mop arm retracts to the top of the robot rather than lifting a few millimeters, so it can mop and vacuum in one pass without routing around rugs.

Published specifications

Stated suction
Stated only as 100 percent stronger than the Roomba Combo i seriesiRobot publishes no absolute suction figure for this model, so it cannot be compared with a Pa rating from any other brand. That is a limitation of the data, not a criticism of the machine.Source: iRobot Roomba Combo j9+ product page — power-lifting suction claim (retrieved 2026-09-01)
Max climb height
Not publishediRobot states no threshold or obstacle climbing height for this model on its own product page.
Mop lift
Auto-retract — the mop lifts to the top of the robotiRobot describes it as an Auto-Retract Mopping System with back-and-forth pressure mopping. No millimeter figure is given because the pad leaves the floor plane entirely.Source: iRobot Roomba Combo j9+ product page — mopping system (retrieved 2026-09-01)
Main brush
Dual multi-surface rubber brushes with an edge-sweeping brushSource: iRobot Roomba Combo j9+ product page — brushes (retrieved 2026-09-01)
Navigation
PrecisionVision Navigation on iRobot OSSource: iRobot Roomba Combo j9+ product page — navigation (retrieved 2026-09-01)
Stated runtime
Not publishedNot stated on the iRobot product page.
Dustbin
Not publishedNot stated on the iRobot product page.
Body height
86mm (3.4in)Listed dimensions 3.4 x 13.3 x 13.3in, 7.5lb.Source: iRobot Roomba Combo j9+ product page — dimensions (retrieved 2026-09-01)
Dock
Multi-functional base that empties the bin and refills the mop tank, stated at up to 60 daysSource: iRobot Roomba Combo j9+ product page — base (retrieved 2026-09-01)

What it does well

  • The mop retracts fully onto the body — the most complete answer to wet carpet anyone sells
  • Dual rubber brushes, which do not wind hair the way bristle brushes do
  • Sixty-day stated self-empty interval

What it does not

  • iRobot publishes almost none of the numbers this site compares on — including any climb height
  • Suction is quoted only as a relative claim ("100% stronger" than an older model), which cannot be compared across brands

Who it is for

Mixed carpet and hard floor where you would rather the robot just handled both in one run.

Skip it if

You want to compare it on specification. iRobot publishes no suction figure, no climb height, no runtime and no bin capacity for this model.

Check price on Amazon

#ad how we are funded · no live price right now, so we show none

Full iRobot Roomba Combo j9+ write-up

Questions people actually ask

+ How often should I replace a robot vacuum brush?

When the fins have gone soft and rounded or have taken a permanent flat spot, not when an app reminder fires. A brush that still has sharp edges and clears hair easily is still working, whatever the calendar says.

+ Are third-party robot vacuum parts any good?

For filters and mop pads, generally yes and much cheaper. For the main brush, fit matters more than material — a roller at slightly the wrong diameter either does not reach the floor or drags. For batteries, buy the manufacturer's.

+ How much do robot vacuum parts cost per year?

It depends on the model, the usage and where you buy, so any single figure we printed would be wrong for most readers. What we can tell you is which design choices reduce the count: an anti-tangle brush, a bagless base, and a dock that washes hot and dries.

+ Is a bagless self-empty base cheaper?

Yes, there are no bags to buy. It is worse in an allergic household because emptying it releases the fine material you collected, which a bag keeps sealed.

+ Can I wash a robot vacuum filter?

Only if the manual says that filter is washable, and only if you dry it completely before refitting. Washing a non-washable filter destroys the media, and refitting a damp one grows exactly what you do not want in an air path.

Sources