Cut the hair off the brush roll.

Yes, that’s the actual answer. Robot vacuums tangle because hair wraps around the brush roll, and the only real prevention is regular maintenance. You can fight it with design features or tools, but nothing replaces just checking the brush every week or two.

Some models are better than others—brushless designs or rubber fins instead of bristles tangle less. But they still pick up hair that wraps around bearings and axles. The iRobot Roomba j-series has a “tangle-free” brush that helps, but it’s not magic. Pet owners, I’m looking at you: you still need to pull hair off the rubber fins.

If you want to reduce tangling, get a model with a “tangle-free” brush roll (like the Roborock Q series or Roomba j7+). And buy a cheap seam ripper or a small grooming rake. Run the vacuum daily to prevent hair from building up into a wad. But honestly? The simplest way is to just cut the hair off the brush roll once a week. Takes thirty seconds.

Your robot vacuum is a tool, not a miracle worker.