It can be one of the toughest things about going out to dinner: when to tip and how much? It seems the rules are always changing. Now, a new type of receipt is showing up at all sorts of restaurants and stores; the receipts have a line designated for tips. If the line is there, does that mean you're expected to tip - even if you're just buying a bottle of water? We went to some local experts to answer this week's Good Question.

Like anyone who works behind a counter or on a restaurant floor, Rocket Bakery manager Nina Volostnova depends on your spare change at the end of her shift to round out what she makes on her paycheck."I think anybody who works in the restaurant business and the customer service industry lives on their tips," she explains. "So, of course we rely on it."Tipping for good service goes back centuries, possibly as far back as the Roman Empire. In more modern times, TIP is actually an acronym: it stands for To Insure Promptness. But, how much to tip can be confusing and the rules seem to be changing all the time."The guidelines are: 15 percent is standard or average, 20 percent if they've given excellent service, 10 percent if they've done less than excellent service," says Merrily Bjerkestand, a Spokane etiquette instructor. Bjerkestrand operates the Northwest School of Protocall, providing etiquette classes and training to everyone from kids to hotel professionals and corporate clients. She says tipping is always optional, but not tipping says more about the customer than the service."You learn a lot about people," explains Bjerkestrand. "I love to watch people when they tip or in restaurants to see how they're going to tip or how they're going to treat eachother."Tipping at a nice restaurant is a no-brainer. Tipping for a custom cup of coffee is just a good idea. But, those receipts with the special line for a tip are making things a little more complicated. For example, I bought a bottle of water and a pre-made sandwich on my way to work today. I paid with a credit card and the receipt had the line for the tip. Even though no one made me anything or served me anything, am I still expected to tip?"If you're just buying a bottle of water, I don't expect a tip," says Volostnova. "But, if someone comes in and buys a quad, sugar-free, extra-hot... then you are expecting that person to tip you out."Okay, so what do you do what that tip line? Leave it blank? Fill it in with zeros? Write "no tip" in big letters? Rules of etiquette sugest you simply leave it alone."Even if you pay with debit, you don't have to write a tip. You're welcome, if you feel free, to draw a line if you don't trust and you think they're going to go back and add in more," says Bjerkestrand. "But, if you write the total in, the total is the total and that's what they're going to go by."And, when in doubt, a simple smile and thank you could be the tip the server will remember."Even if you don't have a lot of money to contribute to the tip, at least be gracious in your words and respectful and appreciative for what they do," says Bjerkestrand. "Because that will speak more than the money will." --Merrily Bjerkestrand has some additional tips about tipping. She says you should tip:-Headwaiters, waiters, bartenders, wine stewards, pianists or strolling musicians, coatroom and restroom attendants and valet parkers-Hairdressers, manicurists, barbers, personal trainers, taxi drivers, moving men, shoeshine personnel and building personnel like handymen if they perform a service.Don't Tip:-Doctors, dentists, travel agents, accountants, realtors, travel agents-Owners and managers of businesses-Airline flight attendants-Train conductors-Federal Government Employees-Plumbers, electricians or other service employees-Hospital staff members