Americans have become more choosy about whom and how much to tip at the holidays, according to a nationally representative phone survey conducted by the Consumer Reports National Research Center.

How much to tip and whom to give it to has always been a tricky decision, one that may get harder in these tough economic times. During the 2008 holidays fewer people than in the previous year tipped their newspaper carrier, barber, mail carrier, hairdresser, manicurist and garbage collector.

The poll of more than 1,800 U.S. residents was conducted in January, shortly after the 2008 holiday season, when respondents could best remember what they gave. A separate survey CR conducted in October 2009 shows that the downward trend might continue: 26 percent of Americans who usually tip or give a gift to a service provider said they would spend less this holiday season than last. Just 6 percent said they planned to spend more.

The big recipients were house cleaners, with 58 percent of respondents who employ them tipping them with cash, check or a gift card and 17 percent tipping them with a gift last year. House cleaners also received a larger gratuity than other service providers, averaging about $50 or an equivalent gift per tip.

CR found other service providers included in the survey received, on average, tips valued between $10 and $40 per gift. Average cash or noncash tips were also smaller for some occupations. The median tip value for manicurists was $10, half the amount given during the prior holiday season; the median tip for pet-care providers dropped from $30 to $25. A few of the tippers surveyed bucked the trend, giving as much as $500.

“Families are looking for ways to balance their financial concerns with the need to thank people who have helped them during the year,” said Tobie Stanger, senior editor at Consumer Reports. “This year, tipping is more of a challenge than ever, but CR’s survey shows that people are still trying to do it, for the most part.”

Rounding out the list of other service providers who received cash, a check or a gift card and who typically receive holiday tips in the survey: hairdresser (36 percent), manicurist (33 percent), newspaper carrier (30 percent), barber (26 percent), pet-care provider (26 percent), child’s teacher (20 percent), mail carrier (13 percent), lawn-care crew (18 percent), and garbage collector (6 percent).

Although more than half of respondents gave something to a teacher, most gave a gift instead of money. (School districts may discourage cash gifts.) Postal workers can accept noncash gifts or gift cards worth $20 or less. Choose gift cards with care: Bank-issued cards may expire or have fees, and retailer-issued cards might be useless if the store goes under.

If you’re giving less this year, you can still say thanks with a card or homemade gift. CR’s readers have reported plans to make wreaths, Christmas-tree ornaments, or specialty foods. Reader Cale Johnson of Seattle, for instance, recently made three-dozen jars of pear chutney from a bumper crop in his back yard. “It’s as though the tree sensed I could use a little help with my holiday gift giving,” he said.