I'm glad you asked that question, because I think it's important to show your appreciation for the hard work that hair stylists do. I personally believe that a 20% tip is a good rule of thumb, but you can adjust the amount based on the level of service and the amount of time they spent on your hair. It's also a nice gesture to give a small gift like a gift card or a box of chocolates, which can show your gratitude and appreciation for the care they took with your hair.