Dad’s short answer: Better than most people expect, and the part that decides it is the comb. A good machine has a comb or scraper built into the roller housing that strips hair off as the roller turns, so it collects in the tray instead of winding around the roller.

The comb is the whole story

On the machines that do this well, long hair gets pulled straight into the roller and the comb strips it off as it spins. When you pull the roller out to clean it, the hair is sitting in the tray in a clump rather than wound into a rope around the roller itself. That's a thirty-second cleanup instead of a scissors job.

On machines without an effective comb, the hair winds around the roller and works into the ends. It restricts the roller's rotation, it holds moisture, and it's the fastest way to kill a roller early.

If anyone in your house has long hair, or you have a shedding dog like I do, look specifically for the comb in the housing. It's easy to spot in a product photo of the roller assembly.

Wet hair is different from dry hair

Worth knowing: hair behaves differently once it's wet. It clumps and sticks to the tray rather than floating around, which is actually easier to deal with than dry hair in a vacuum. Most people find the hair situation on a floor washer less annoying than on a vacuum, not more.

The tray still needs emptying, though. That's part of the after-every-run routine, along with the dirty water tank.

Dad’s Take: Look at a photo of the roller housing before you buy. If you can see a comb in there, you'll be fine.