A: Many vendors will discuss gratuities up front with you and stipulate a percentage in their contracts, which is then divvied up among those who worked the event. Even so, it's a good idea to ask about tipping norms before you sign up for vendors' services. As a general rule, wedding professionals who own their own businesses—planners, bakers, florists, photographers—usually are not tipped. Meanwhile, food and other service providers, such as caterers, waitstaff, bartenders, musicians, and limousine drivers, are. When not stated in the contract, a tip of 15 to 20 percent of the food and beverage bill would be tipped to the caterer, who then tips the waitstaff. (If the waitstaff is exceptional, you can give them each an extra $20.) Also distribute 10 to 15 percent of the bar bill to among the bartenders. Reception musicians and DJs are generally tipped $20 to $25 each.
A few other people not to forget: Drivers who deliver the flowers and cake should be given $5 to $10 if all goes well. Coat-check, bathroom, and valet-parking attendants should be tipped 50 cents to $2 per guest. (As a courtesy to guests, distribute tips ahead of time, and place discreet signs in each related area stating that gratuities have already been covered.) —Anna Post, The Emily Post Institute