Cash is the best way to say “Happy Holidays” to those whose job it is to make others lives easier, experts and recipients told CNN.

“You tip the people who perform services for you year-round, who are there for you when you need them and whom you have a valuable relationship with,” Peter Post, director of the Emily Post Institute and author of Essential Manners for Couples told CNN.

In addition to the cash, Hilka Klinckerg, founder of Etiquette International, suggests including a short note of thanks and giving the tip in person whenever possible, CNN reports. MSNBC financial editor Jean Chatzky, suggests writing letters of appreciation to an individual’s employer, especially if they work for a company and have gone out of their way to be helpful.

Of course, there is no obligation to tip; just as there is no obligation to give a gift. Some people, like postal workers, can’t even accept tips. (Postal workers can accept non-cash gifts up to $20 in value.) Some teachers may fall into the no-tip category, as well, so check with your school district before handing out tips. Thank you notes and letters of appreciation are especially important if you can’t afford to tip or tip much this year.

If you do tip, you don’t have to go broke dong it. A good rule of thumb to follow is to tips the equivalent of one or two visits or weeks depending on how frequently you use the service they provide. For instance you might tip your hair stylist the equivalent of one visit to the salon, while you might tip your day care provider the equivalent of a couple of weeks worth of day care.

The only place this rule of thumb does not apply is in the restaurant and hospitality industry. These folks typically depend on tips as part of their regular income, and should be tipped every time you use them. Fortunately there are some general rules for this too. Most people seem to feel that 10 percent of the total bill is the absolute minimum a wait person should be tipped for providing adequate service. Good service, or waiting on groups larger than six people, generally merits a tip that is equivalent to between 15 and 20 percent. Great service deserves 20 percent or more. If, however, you have a favorite restaurant or stay at the same hotel every month when you are in town meeting with clients, you may want to consider adding something extra to your tips during the holiday season. Here is one place where your generosity is likely to really pay off.

For more help determining how much and who to tip this season, visit The Original Tipping Page.