If you're wondering whether or not to tip the owner, we've got bad news: The jury is still out. According to Diane Gottsman, national etiquette expert and owner of The Protocol School of Texas, "It's always subjective."

Years ago, omitting a tip when the owner serviced you was completely acceptable. In fact, it was sometimes considered an insult. But now owners are more hands-on, says Gottsman. "If you ask, most of the time an owner appreciates the tip," she says.

Phillips, on the other hand, disagrees. "I think the owner should be charging enough off of the service that [a tip is unnecessary]. I think it's very odd to tip the owner," she says.

Gottsman says the best way to avoid confusion is to ask the owner if they accept gratuity, or to check with the receptionist when you make your appointment.

Consider this scenario: You're headed to your usual salon, where you always place a $20 bill in the hand of your stylist when she's done with your service. But this time, she has an assistant shampoo you, and a colleague take over the blow-dry while she sorts out another client. Suddenly, anxiety strikes. Do you need to tip all three of the people working on you?

Usually, yes, says Fontana. The standard tip for a shampoo is anywhere from $3-$10 (a great scalp massage tends to incite generosity in clients), and if separate people did your cut and color, you should pay them the standard 15 to 20 percent of that fee, if their service warrants a good tip.

If, at the end of your service, you're panicked over what to leave with whom, ask the person at the front desk before you start shredding that $20 bill into thirds. She or he is used to handling tipping situations and can advise you on the standard policy (and perhaps provide some change).

In days of instant transactions and one-click buys, it seems old school to have to bring cash separately to tip your service provider. But if you don't, you might be shafting the person who provided your service.

"If you tip on a credit card, the business is paying the merchant's fee and all of the FICA taxes for the employee on the credit card fee," says Phillips. "For example, if the business takes in $1,000 in gratuity, and we then have to pay that to employees, it will cost the business $1,200 to pay out $1,000 dollars."

That means the extra fees get subtracted from the tip you left, which is why most businesses won't accept a tip on a credit card.

Instead, clients can leave a tip in envelopes provided by most spas. Why the unnecessary clandestine paper transactions? "From an IRS perspective, the owner never even wants to see that cash," says Phillips.

There are a few situations when leaving that line on the check blank should be guilt-free:

-At an all-inclusive resort
All-inclusive means all-inclusive, even if you spend an entire week getting pampered at the spa. Don't feel bad about failing to slip your masseuse a $20 -- all-inclusive resorts add an 18 percent gratuity charge to your bill at the end of your stay.

-When it's not their policy to accept tips
Phillips, who began her career as the owner of a spa that didn't accept tips, says that spas do so in order to provide a stress-free experience to the client. "If you've had multiple services, and you're a little spa drunk at the end, all of a sudden now you're doing math and it ends the service on a different note," she explains. Before you book the service, call ahead and ask what the tipping policy is.

-When you had a bad experience
For spa and salon owners, the bottom line isn't "how much of a tip did I make today?" Instead, they want repeat customers who bring in referrals. If you didn't have a good experience, you don't have to tip. You should, however, ask to speak to the manager or owner instead of leaving a passive-aggressive $0.50 tip to express your feelings. Phillips says that service providers are apt to think that a client is cheap if they leave a bad tip, rather than it being a reflection on their service.

-When they're fixing a mistake
Sometimes, a haircut or color doesn't turn out the way a client envisions, and the hairdresser will offer to fix it. In this scenario, Fontana says it's okay not to tip; In fact, he will refuse tips if someone requests a revision. "If the client has to go back, it's because they don't like it and you didn't do your job properly in the beginning, so you should not take any more money from that person," says Fontana.

-The ambiance wasn't up to standard
If the person working on you was doing a great job, but the atmosphere wasn't ideal, it's not their fault. The person to address those concerns with is the owner or manager, not the service provider. "You don't get a refund on your airline seat if there was a crying baby. If the service provider was good, tip them," says Phillips.