Who doesn’t love going to the hair salon or getting their nails done? It’s the little luxuries that can make you feel like a million bucks. But how many times have you found yourself staring at a beauty treatment receipt wondering, “How much am I supposed to tip, again?” The answer isn’t black and white.Sure, there’s the 15 to 20% rule for most services, but what about the ones that cost hundreds of dollars and require multiple sessions? From waxing to eyebrow threading, gel manicures, facials, blowouts and even laser hair removal, we spoke with eight beauty experts to get the full rundown on exactly how much you should tip.