If you don't know already, it it highly likely that your shower or sink drain is letting hair slip by. This probably means that somewhere nearby, there's a slimy hairball slowly growing. These drain covers are classy and effective and made for the different drains in your house. I know there are other objects that purport to capture all the hair, but I haven't tried them because they seem...icky?
(if I should switch, please do let me know though 🙃 — I've seen high ratings for things like "The TubShroom Ultra"