I think I've posted about this once before a long time ago, but I remember reading an interview with Melissa Hill once where she was asked why she did so many facials. She said she actually didn't like them at all, but that she didn't know when she started off in porn that she could refuse to do them, so pretty much every scene wound up ending in a cumshot to her face. And by that point, it didn't really make sense to stop doing them.