Hair Cuts at Great Clips (or where ever) do you tip?

I wear a pompadour & since any hairstylist I've ever been to is clueless on them, I go to an old school barbershop. Perfect pomp & cleaned up with a straight razor. He even keeps Murrays Pomade (read: hair grease) on hand just for me. Not too many places know how to cut retro hairstyles so if the cut is $15 I always tip $5.