Some will, always — anyone promising zero tangle is selling you something. But the gap between a good anti-tangle roller and a bad one is enormous, and it’s the one spec I’d shop hardest on if anyone in your house has long hair.

What good and bad actually look like

On a well-designed roller I’m pulling a small wrap off the ends about once a month, and it comes off in one piece by hand. On a poorly designed one it’s a scissors job every week, the hair works its way into the bearing at the end of the roller, and the motor starts to strain. That’s how rollers die.

The design that works uses a rubber or fin-style roller rather than bristles, with a comb or scraper that pushes hair toward the ends where it can be removed easily. Bristle brushes grab hair and hold it in the middle, which is exactly the wrong place.

Two spots people forget to check

The axle ends are the first. That’s where hair collects into a hard little donut that stops the roller turning freely. Most robots have a cap at each end that pops off; check under it monthly.

The side brush is the second. It’s a spinning arm out at the edge of the robot and it wraps hair constantly, especially long human hair. It’s cheap to replace, but a wrapped side brush throws debris instead of sweeping it inward, so it’s worth clearing.

The wheels and front caster round it out. Hair around a wheel is one of the most common reasons a robot starts getting stuck in places it used to handle fine.

Dad’s Take

If somebody in your house has long hair, the roller design matters more than every other spec on the box combined.