Here’s a tip: Stop being a cheapskate.

Americans have a tipping problem. One in five people who go to a sit-down restaurant say they at least occasionally completely stiff the waiter or waitress, according to a survey of more than 1,000 adults by CreditCards.com. What’s more, nearly one in three never tip hotel housekeeping or their barista, and more than one in 10 never tip their hair stylist or barber.

This is, quite simply, wrong and rude, say etiquette experts. Waitstaff, hotel housekeeping and hair stylists should always be tipped, unless they do something deplorable. Waitstaff at a sit-down restaurant should get 15% – 20% of the total bill; hotel housekeeping gets $2-$3 per day at a modest hotel, $5 a day at a five-star hotel; and hair stylists and barbers get 15-20% on the total cost of the cut, says Pamela Eyring, the president of the Protocol School of Washington.

Barista tipping rules are a bit more complicated. “If you order a regular coffee with cream, tipping is optional,” says Eyring. “If you give a complex order and the barista makes it perfectly, you can tip up to $1.00 per beverage.” Adds etiquette and relationship expert April Masini, “if your order is more than two drinks, put a few dollars in there. If you’re a regular and you’re in more than twice a week, put a five in the jar every few visits.”

Interestingly, certain groups of people are better tippers than others — in particular Republicans, men and people living in the Northeast. They all tip a median of 20% when dining out at a restaurant, compared to just 16% for women and 15% for Democrats and southerners.

The differences between groups may come down to income, says Matt Schulz, CreditCards.com’s senior industry analyst — as groups that tend to have more money tend to tip more. Plus, he adds, “tipping is pretty confusing — a lot of people don’t know who to tip and how much and when to tip.”

For all of you in that group, Moneyish put together a helpful tipping guide of people — besides waitstaff, hair stylists, baristas and hotel housekeeping — that you should be tipping..

  • Hair stylist’s assistant: Roughly $5
  • Hotel concierge (if they fulfill a complicated request for you): $5-10 and sometimes more
  • Courtesy shuttle drivers: $1 to $3 per bag
  • Delivery driver: On orders under $20, tip at least $3; on higher orders, 15% but not less than $5
  • Bartender: $1 a drink
  • Hotel bellhop: $2-$3 per bag
  • Taxi/Uber/Lyft driver: 10%-15%
  • Delivery service: $3-$5 (and more if it is a large or extremely heavy item)
  • Airport baggage handlers: $2-$3 per bag