Dave Ramm just wanted to be nice. A native of Lincoln, England, Ramm, his wife and 6-year-old son had been touring Asia for about six months when they met with his Vietnamese in-laws for a short tour of the Perfume Pagoda in Hanoi.

They paid in advance for the tour, which included a leisurely ride to the pagoda entrance in a boat rowed by a local woman. A few hours later, as arranged, the same boat owner took them back to their taxi.

“When we arrived at the dock, I decided to give the lady a tip, which I thought was only fair as she’d been nice,” Ramm said. “I don’t tip for the sake of tipping. If someone is nice and has given a good service, then I’ll tip.”

The woman took the tip — about 50,000 dong (a couple of U.S. dollars) — and threw it back at him. As the woman yelled, the tour guide told him the tip was rejected not because of a cultural aversion to tipping but because the tip itself wasn’t up to the woman’s expectations.

The woman followed Ramm and his family as they headed to the taxi, screaming that she normally got $10 or $20 in tips. She blocked Ramm’s mother-in-law from getting into the taxi and held back his wife.

“At this stage, I stepped in, as did the taxi driver and our guide, and they saw the lady off, who by now was saying that, yes, she would now accept our previously offered amount for a tip,” Ramm said. “This was not forthcoming.”

Just how much, when and whom to tip is one of those sticky questions that plague travelers. Tip too little and riskembarrassment. Tip too much and be pegged ethnocentric or, worse, a patsy. Tip at all in some regions and offend the host.

Lesley Carlin McElhattan, a travel etiquette expert for TripAdvisor, said the only way to prevent a potential tipping faux pas is to do your homework. Ask other travelers, double check with tour guides and read articles about tipping. It also doesn’t hurt to keep a few small bills on hand, just in case.

“I recently saw someone tip a hotel parking valet with $20 and ask for $18 back,” McElhattan said. “I understand the ‘I just went to the ATM and have no small bills’ problem, but if you’re in this situation, get change from the front desk.”

Muddying the issue even further, Americans have a reputation for big tipping, even in regions where the custom isn’t common.

“Unfortunately, nowadays when traveling down in Australia, the Americans just have to tip even though the Australians are earning real good salaries,” said Sandy Lucas of Maryland, a native Australian and travel specialist with Glyndon Travel. “They are starting to expect it, but not from me.”

Australians will likely get a tip from frequent traveler Tim Gittins, though.

Gittins travels from his St. Louis home about 200 days a year for business and often takes personal trips during his eight weeks of vacation time. Clearly an experienced traveler, Gittins drew fire — and a fair amount of support — in July 2009 when he posted on Lonely Planet’s Thorn Tree travelers’ forum: “Having class is all about manners, regardless of where you come from. Some have it, some don’t, but to be from the West and not tip says more about you than the person needing the tip.”

To help navigate the international rules of tipping, follow this brief guide to tipping customs around the world.

China

Tipping in China was once refused, and tippers risked having a waiter chase them on the street to return the “forgotten” coins. But times — and tips — they are a-changin’.

Pru Goudie of OnTheGoTours.com said she advises clients that tipping often makes up a significant part of people’s wages in this part of the world, “So it’s important we get it right.”

Some restaurants and hotels in Chinese cities, such as Hong Kong, already include a small service fee in the bill. If so, additional tipping is unnecessary. If not, leaving behind 10 to 15 percent of the bill total is fine for wait staff, as is a dollar or two for bellmen at hotels, according to TravelChina Guide.com. Tour guides or drivers also welcome a small gift, such as candy.

Australia

In Australia, tipping is generally not practiced, said Glyndon Travel’s Lucas. Often, a simple “thank you” to the person who holds open the door or carries your luggage will suffice.

“There is an exception,” Lucas said. “If you are dining in a very expensive restaurant and all dressed up, yes, leave a tip.” But that tip doesn’t have to meet the 20 percent standard of the United States. Rounding up the bill a little is fine.

In a taxi, round the fare to an even coin and keep in mind that loading luggage in the trunk is included in the charge, Lucas said.

United Kingdom

The British Hospitality Association’s code of practice dictates that restaurants explain service charges in print and detail how much of the amount is given to staff and whether any is kept by the restaurant. “Any attempt by the restaurant to encourage diners either to add more to this amount or leave a further cash tip should be ignored,” said BHA spokesperson Miles Quest.

If there isn’t a service charge, go ahead and leave a tip of your own, Quest said. At fine-dining restaurants, it’s proper to give the maitre d’ a tip for special effort. In U.K. pubs or cafés, a proper tip would be rounding up the bill by a few coins.

When he’s at home in England, Ramm, who had the unfortunate encounter with the water taxi in Hanoi, said British bar patrons often offer to buy the bartender a drink: “In pubs, the only people who tip are those trying to be flash or those who fancy the barmaid.”

When it comes to hotels, tipping gets more discretionary. Luggage porters usually warrant a pound or two per case, and valets or others who provide individual services might expect a small reward.

Taxi drivers will expect a 10 percent tip, as will private coach drivers and tour guides (one or two pounds per person).

Europe

The question of how much to tip — or whether to tip at all — keeps European travel forums buzzing. If you’re not sure, 10 percent is a safe bet. For housekeeping services, one to five euros is customary.

Many European restaurants add a service charge of between 10 to 15 percent to the bill. This fee, though, usually goes back to the restaurant management, not necessarily to the wait staff. If service was exceptional, it’s a nice gesture to leave an additional 10 percent for your servers, but remember, unlike in the United States, tips do not comprise the bulk of pay for European wait staff.

About 5 percent is a safe bet for European taxi drivers, as is rounding up the tab to the nearest coin. In pubs, keep an eye on the other patrons and follow their lead, but if the bartender keeps your glass full and your heart merry, offer to buy him a round.

Japan

Tipping staff for services — from waitresses to bellboys — is not customary in Japan, according to the Japan National Tourism Organization. Instead, about 10 to 15 percent is added to bills at luxury hotels and restaurants. This includes a charge for housekeeping.

“There’s basically no tipping, period,” TripAdvisor’s McElhattan said. “If you leave money on your table, your waiter might feel he or she needs to track you down and give it back to you.”

South America

Many South American restaurants already add gratuities (about 10 to 15 percent) to bills, said OnTheGoTours.com’s Goudie, but that doesn’t mean additional tips aren’t accepted. Most South American tourist and service staff are paid minimum wage; a small tip would be welcome. Goudie advises travelers to leave a few dollars for tour leaders and drivers for jobs well done.

United States

Even seasoned travelers might stumble on domestic gratuity etiquette. Most of us know to leave 20 percent for excellent waiters, but what about hotel staff? Does everyone — from the person who brings a bucket of ice to your room to the housekeeper who takes the time to triangle your toilet paper — expect reward? McElhattan offered the following advice for hotel guests:

Offer bellmen a $2 tip for carrying your first bag and an additional $1–2 thereafter. Tip the doorman $1–2 for arranging a cab, loaning an umbrella or other services. Have $2–5 on hand for the valet when he retrieves your car or if you want a special service, such as upfront parking, when you drop it off. For quick extra services, such as that ice bucket delivery, a dollar or two would be nice, but isn’t necessary.

Daily housekeeping tips depend on the hotel and the mess, but about $2–5 per day is typical. “In my experience, a daily tip tends to get you better service during your stay — and also ensures the maid who services your room each day gets tipped, not just the person who cleans it the day you check out,” McElhattan said.

The concierge’s tip is more discretionary. “If he merely answers a quick question, like ‘Where’s the nearest metro stop?’ don’t worry about it,” McElhattan said. “Hard-to-get dinner reservations or theater tickets would merit $10 at least.”

Still worried about over-tipping? At least you’re not alone. BHA’s Quest sums it up this way: “I think anyone traveling abroad and using strange currency in an unfamiliar environment tends to over-tip rather than under-tip.”