A well-maintained quality robot should give you four to six years. Budget ones often don’t make it past two. The battery and the dock usually fail before the robot itself does.

What actually fails, and in what order

The battery goes first in most cases. Runtime drops off gradually and then falls off a cliff, and on many models the battery is replaceable if you can get the part.

The dock is often second — the suction motor in a self-empty base works hard in short bursts, and the mop washing hardware in an all-in-one dock has pumps and valves that are more failure-prone than anything inside the robot.

The roller bearings are third, and they’re accelerated dramatically by hair that never got cleaned off the axle ends. That one is genuinely in your control.

I keep over a hundred robots in long-term testing in the studio basement, running two to three times a day and deliberately skipping some maintenance to simulate years of wear. That’s where these patterns come from.

Run the parts check before you buy

This is the step almost nobody does and it matters more than most specs. Before you commit to a model, search for its replacement main roller, side brush and filter and confirm you can actually buy them today.

Some brands keep the full parts catalog stocked for years. Others quietly stop, and a great machine you can’t get a roller for is a great machine you throw away. This has caught out plenty of people who bought a well-reviewed robot from a brand that exited the category eighteen months later.

It’s also worth checking whether generic equivalents exist. On popular models they usually do, and they’re often perfectly good — I test both and list them on review pages.

Dad’s Take

Check that you can buy a replacement roller before you buy the robot. Takes two minutes and it’s saved me from recommending some real duds.