According to experts, apparently long hair can get trapped in pipes leading to a less than optimal drainage situation.
The solution here, according to the same experts, is to pour a liquid called “Mudin” down the drains twice a year. Or, as the experts said, “or, for you, every three months”.
I’m just reporting what the experts said. I take no responsibility for any negative effect this advice may or not may have for you.
They left me a bottle.