MIAMI (CBSMiami) — How much do you tip? A new study finds some people are more generous than others.

Ted Rossman with says, “We found that in general, men and millennials are the worst tippers. Which means that women and baby boomers, generally speaking, are better tippers.”

READ MORE: NBA fines Miami Heat $25,000 for violating 'bench decorum'

And who gets a tip varies greatly. Seventy-seven percent of all people surveyed say they always leave something to servers at a restaurant. But the numbers drop with food delivery people, hairdressers and taxi and rideshare drivers. Only about one out of four people tip hotel housekeepers and coffee shop baristas.

Joseph Frisa almost always gives extra.

“It’s got to be really bad service for me not to leave a tip,” he says. “The guy’s gotta throw the food at you before I don’t leave a tip.”

READ MORE: Man faces several charges including pointing laser at BSO aviation unit

Brandon Baig says it depends. If service is bad, he says, “I’ll leave a small amount of tip or no tip at all.”

Rossman says, “Here’s a general rule of thumb. If somebody is making things easier for you, they’re going out of their way to do something nice for you, I would feel compelled to give them a little something. And I think, in particular, if this is someone you are interacting with regularly, that’s all the better.”

Rossman says that can lead to better service.

Even though millennials are less likely to give a tip, the study found when they do tip they leave a higher percentage.

MORE NEWS: Miami ex-Proud Boys leader Henry 'Enrique' Tarrio to stay jailed until Capitol riot trial