Tipping is a practiced social custom in the United States. Tipping by definition is voluntary – at the discretion of the customer. In restaurants offering traditional table service, a gratuity of 15–20% of the amount of a customer’s check (before tax) is customary when good to excellent service is provided. In buffet-style restaurants where the server brings only beverages, 5% is customary. Higher tips may be given for excellent service, and lower tips for mediocre service. In the case of bad or rude service no tip may be given, and the restaurant manager may be notified of the problem. Tips are also generally given for services provided at golf courses, casinos, hotels, spas, salons, and for concierge services, food delivery, and taxis. This etiquette applies to service at weddings where the host should provide appropriate tips to workers at the end of an event; the amount may be negotiated in the contract.