For a practice that’s roughly traced to the 17th century, tipping remains a surprisingly confusing practice in modern-day America. That prompt — whether on a physical transaction or a digital one — still elicits stress in consumers who aren’t certain who to give the extra money to, and how much.

Maybe you’re comfortable on your home turf, knowing to tip your local barista or neighborhood bartender, but what happens when you’re out of your element? Who you tip while traveling can present a different and challenging roster.

We interviewed etiquette and hospitality experts to clear up some confusion about the custom in America — after all, we’re not born with this information.

“We look for rules, and we look for guidelines, and those are important," says David Coggins, a New York Times best-selling author of the book “Men and Manners.” “But if you already decide that you’re going to be generous or err on the side of generosity, then you’re always going to make a better decision than if you try to think, How little can I get away with?”

Do you know the rules? Test your tipping knowledge with our quiz below, based on information we gathered from the experts.

Is it true that you’re never fully dressed without cash?

In “Men and Manners,” Coggins writes just that: You’re not fully dressed if you have no cash. As Americans appear to be moving toward a cashless future, tipping becomes more of a calculated effort.

“I’m obsessed with not being out of small bills, and I try to think about that ahead of time,” Coggins says.

You have to be mindful about having cash on you so you don’t stiff those deserving gratuity. If you can, stock up on small bills before your trip.

You take a complimentary shuttle from the rental-car lot to your terminal, and the driver unloads your bag from the bus to the curb. Do you tip?

When someone touches your bag, you tip. Founder and CEO of the Protocol School of Palm Beach Jacqueline Whitmore recommends $1 per bag, unless it’s extra heavy (then give $2 per bag). If the driver just drops you off, and you handle your bags yourself, there isn’t a need for gratuity.

You’re on an airplane and the flight attendant serves you a drink. Do you tip?

Keep your singles to yourself on a flight. Most airline staff members are asked to decline tips that are offered.

“The best way our customers can recognize our team members is by sending a note to our customer relations team,” says Ross Feinstein, director of operations communications at American Airlines.

You opt for curbside baggage check from a third-party vendor. Should you tip the attendant checking your bags?

Swann School of Protocol’s founder, Elaine Swann, recommends tipping according to how many bags are handled at curbside check-in.

“When they’re bringing your bags from your car and they’re checking them for you, $2 per bag,” she says.

Should you tip only at the end of a hotel stay?

Tipping time is flexible here. It can be at the beginning or end of a stay. There’s no hard-and-fast rule on when you should tip hotel staff, so make sure you have small bills at the ready to hand out when the situation arises.

You arrive at your hotel by car and leave it with the valet. Do you tip the valet attendant?

You should absolutely tip your valet attendant, preferably when you hand them your keys. This is a great example of gratuity to ensure proper service — you want the valet on your side. Swann recommends tipping valet drivers $3 and up.

“Tip them in the beginning and they’ll always look after you,” says Ben Pundole, vice president of brand experience at Edition Hotels. “The more you look after them, the more they look after you.”

The hotel manager upgrades your hotel room to a suite. Do you tip her?

A hotel manager tends to be a salaried employee who doesn’t require a tip. A clue for who to tip and who to skip is to look at how the hotel employee is dressed.

“I don’t tip someone in a suit from behind the counter,” Coggins says. “Generally, if a person is wearing a suit or their own clothes, I don’t. They’re a manager of some higher position and so you don’t need to tip them. But if it’s a person in a uniform, you generally do.”

A bellhop greets you in the hotel lobby and takes your bag(s) upstairs to your room. Do you tip?

How much will depend on what kind of hotel you’re at, and what kind of service you’re getting. Did they drop your bags and go quickly? Did they help you unpack, or share helpful details about the room and hotel? Pundole recommends up to $10 for a tip at a luxury hotel.

Not everyone wants the help, and that’s okay, too. “I used to avoid the bellmen and want to do everything myself," Pundole says. But ultimately, remember that they’re here to help. “They’re proud to be standing at the front of something great and being the first point of contact."

You’re staying at a hotel and housekeeping cleans your room daily. Do you leave a tip?

Not everyone knows to tip the cleaning staff, or they choose not to for various reasons. But according to all of our experts, you absolutely tip housekeeping. It’s a thankless hotel job that often gets overlooked.

In his early traveling days, Coggins didn’t know to tip housekeeping, an error he’s still embarrassed about today. It’s now natural for him to tip housekeeping at every hotel.

“Some people avoid it because they think they’re doing it incorrectly, or they don’t know if it’s going to be appreciated, or they don’t even have the pleasure of handing it to someone,” Coggins says.

“They work really hard. They work long hours,” Pundole adds. “There’s a level of expectation that they do an exemplary job. They deserve it.”

Pundole recommends tipping $10 per day of your visit.

Do the same rules of tipping apply to all-inclusive resorts and cruises?

All-inclusive properties and cruises can come with rules of their own.

“If it’s included, it’s included,” Coggins says. “It depends on the nature of your relationship with a person" at that all-inclusive accommodation.

Coggins recommends giving a particularly accommodating staff member a personally addressed envelope with a tip and thank-you note at the end of your trip. You could also send the person a gift after you get home, if you want to show thanks without turning the gratitude into a financial transaction, Coggins suggests.

While some all-inclusive vacations may encourage tipping, some may forbid the practice. The information should be provided to you on the property’s or cruise’s website, or in an in-room guide and directory for guests.

“A lot of times the cruise line will give you a guideline on tipping,” Swann says. “They break it down day by day. Server by server. Follow the guidelines of the cruise line. As far as the rest of the waitstaff is concerned, you would tip the same way on land — if the cruise line allow it.”

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