Robot vacuums are bad news for thick shag carpets.

No. Not really.

Most robot vacuums have a low profile and rigid brushes. Thick shag will either stop them dead—sensors get confused, they get stuck on the fibers—or, worse, the brushes get tangled in the carpet and the robot just sits there whirring uselessly. Even the ones that claim “high-pile” mode struggle with anything past medium fluff.

If you have a deep shag, your best bet is a canister vacuum or a cordless stick you can push manually. The robot is not saving you time here; it’s making a mess.

Don’t let the marketing convince you.