Especially if you've had more than one service, divvying up the tip can be a challenge—which is why spa owners tell us they're happy to take over. "Tell us what percentage you want to tip, and we'll add it to your bill and distribute it to everyone for you," says Olga Lorencin-Northrup, owner of Kinara Spa in Los Angeles. (Your massage therapist or aesthetician will likely be with a new client by the time you're ready to leave, so it wouldn't be possible to hand her a tip in person anyway.) The standard is usually 18 percent, 20 percent if you were particularly impressed with the service. It doesn't hurt to ask whether gratuity is included, though. Some spas, like the Spa at Yellow Creek in Bath, Ohio, include it in the price of the treatment.