Do you tip the garbage collectors at the holidays? How much should you give your doorman as the year comes to a close?

Year-end tips have become a common practice. About 60 percent of Americans tipped one or more service providers last year, according to a Consumer Reports survey of 2,013 adults conducted earlier this year. They shelled out an average of $45 in tips, the majority of which were in cash, the survey found. Tipping tallies tended to be higher in larger cities.

Yet it's not always clear if you should tip a service provider for the holidays — and if so, how much.

"The best way to gauge to whom you should give tips is to look at those individuals who have helped you throughout the year," said etiquette expert Elaine Swann. "Individuals who helped to make your life easy, assisted you in some shape or fashion."

The first thing is take a look at your budget, which will help determine how many people you can afford to give to, said Lizzie Post, co-president of the Emily Post Institute. (See guidelines below for typical tips by provider.)

"It is about prioritizing your list," she said. "You've got to know what you are able to do. This isn't meant to stress you out and make you feel horrible and guilty. It's really meant to be an opportunity."

Don't just hand over a few bills. That can make things awkward, Swann said.

"Be sure that you present it well, whether it is in an envelope with a thank you and a smile on it, or a card," she said.

While cash tends to be preferred by those on the receiving end, gift cards and presents are also option.

If you are strapped for cash, try to do something, whether it is baking cookies or simply giving a card to express your gratitude. It's really true what they say — it's the thought that counts.

"You may have little on hand in terms of cash but maybe you have skills or supplies that will allow you to make something," Post said.

(It's also worth pointing out that some workers cannot accept cash gifts. Check company policy first. For example, U.S. postal workers are not allowed to accept money or gift cards, only presents worth no more than $20. Nursing home employees and home health workers may not be able to accept cash, either.)

Here are some guidelines for who to tip and how much, thanks to the etiquette experts at The Emily Post Institute.

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Whether you have live-in help, a regular babysitter or use daycare, you should say thanks to those who care for your kids. In addition to any monetary bonus, a gift from your child is always appreciated.

• Au pair or live-in nanny: Up to one week's pay.
• Regular babysitter: Up to one evening's pay.
• Daycare provider: $25 to $70 for each staff member who works with your child.

Some pros say tip up to the cost of one visit. But that makes a lot more sense for those who have regular, fairly inexpensive cuts with a barber than those who shell out several hundred dollars per visit at a salon for a cut, color and highlight. In the latter case, a tip could be somewhere in the ballpark of $10 to $60, or a gift.

• Beauty salon staff: Up to the amount of one visit, divided among the those who work with you.
• Barber: Up to the cost of one haircut.

They take care of your building, fix problems, open doors and receive your packages. So it would be a good idea to acknowledge their hard work throughout the year.

• Doorman: $15 to $80 each.
• Superintendent: $20 to $80.
• Elevator operator: $15 to $40 each.
• Handyman: $15 to $40.

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If your garbage is collected by your municipality, check your town or city regulations to see if cash is allowed. If not, give a gift.

• Garbage collection crew: $10 to $30 each.

If someone cleans your house only once or twice a month, consider tipping them about half the amount of one service. So, if you pay your cleaner $100 to come once a month, think about $50 to $100 as a holiday thank you.

• Regular cleaner: Up to one week's pay and/or a small gift.
• Live-in help: Up to one week to one month of pay, plus a gift.

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Don't forget about the people who take care of your dog and other pets while you're at work or away from home. If you regularly see a groomer, think about tipping that pro, too.

• Dog walker: Up to one week's pay.
• Groomer: Up to the cost of one session.

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They help you get fit, healthy and relaxed — so consider a bonus or gift to your personal trainer or regular massage therapist.

• Up to the cost of one session.