LPT: To allow your towel to dry thoroughly, hang them over a bar with one end hanging lower than the other.
People typically put hooks on the wall or back of the bathroom door and hang their towel or robe there after a shower. Since little air flow reaches the fibers that way, mold can grow and you can't even see it, but you're breathing it in.
Hang your robe on a hanger where there is decent airflow to dry it.
Bonus tip: People tend to go for luxurious, thicker towels for comfort, but a thinner towel will dry much, much quicker, and they're easier to launder.
We found mold growing in a robe as we held it up to the sun. #entertainment