With tourism being the number one industry on the island, tipping is common. Some hotels add a 5 to 10% service charge to your bill; if yours does not, you should leave something for the housekeepers, around US$1 per day being typical. In better restaurants, a 10%-15% tip is usual, with more for exceptional service. Taxi drivers are not tipped. Tour and snorkel guides usually expect a tip, which varies depending on length and type of trip.
