It's hard to feel completely liberated from work and family stresses if you're facing a set of new ones, like whether you're overdressed for your massage or undertipping an aesthetician. Sidestep these little land mines so that nothing sabotages your spa experience.

Take It All Off (Or Don't)
You're led into a changing room, handed a robe, and told to undress…um, all the way? For massages and body treatments, ideally you disrobe completely (that means underwear, too). Most spas offer paper panties to wear during body treatments (like scrubs, wraps, or self-tanning)—they don't cover much, but enough to provide a modicum of modesty. "You should undress only to your level of comfort, though," says Bambi Montgomery, owner of Honey Child Salon and Spa in Chicago and Hive in Los Cabos, Mexico. "We have some clients who bring a bathing suit when they're getting a scrub or wrap." You can also request a same-sex therapist when you book your appointment if that makes you feel more at ease. And you'll never be completely exposed. "Massage therapists and aestheticians are well trained in the art of draping, so they'll uncover only areas they're working on," says Lynne Walker McNees, president of the International Spa Association. If getting anywhere close to naked with a stranger (no matter how adept at draping) is not your idea of a relaxing experience—but you still want some spa pampering—consider Thai massage or shiatsu, for which you wear your own loose-fitting clothes. For a facial, take off your bra (or at least lower the straps) before you slip into a robe, so it doesn't interfere with the neck and shoulder massage.

"Do You Want Microdermabrasion with That?"
Spa prices don't always include add-ons (an enzyme peel here, an oxygen blast there) offered during the course of the treatment. When you book a facial (body services, like massages and scrubs, are less likely to involve extras), ask if it's all-inclusive. More and more spas, like Remède (in New York City, San Francisco, and Aspen), let you book time (30, 60, or 90 minutes) and then customize the facial for your skin—with no extra charges for any of the creams or masks they deem appropriate. If you're going to a spa that has a more à la carte menu, describe your skin concerns when you book the appointment, and ask what add-ons (at what prices) the aesthetician might suggest once she sees you. Then decide ahead of time how much more (if anything) you might be willing to tack on to the base price. Once you're in the treatment room and the aesthetician starts prescribing an extra this or that, you can announce up front what your budget is. "Just be forthright and say, 'I want the best for my skin, but this is how much I can spend today,'" says Jaeger.

The Hard Sell
When you go in for a facial (or sometimes a body treatment), you will likely encounter some form of a product pitch—so be prepared. "If the aesthetician starts mentioning products during your service, just say, 'I'm happy to hear your recommendations, but I'm really here to relax, so please save them for the end,'" suggests Ufland. After your service, if you don't want to purchase anything, ask the aesthetician to write down the products she's recommended (if she hasn't done so already), and let her know that you'll think it over. "Once you say you're not interested right now, they shouldn't say another word," says Ufland. "If they push it, I'd tell the spa manager."

The Chatterbox
If an aesthetician is giving you an earful about her family, her friends, her thoughts on global warming, take the most direct route. "Say, 'Actually, it's been a hectic day, and I was really looking forward to just being quiet during the treatment,'" Jaeger suggests.

Where Am I?
To ensure you don't find yourself shuffling down a dimly lit hall alone in your terry robe and slippers, always ask the person who first directs you to the changing room where you're supposed to go afterward. She'll either wait for you outside or give you specific directions on how to get to your next destination.

The Tipping Point
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.