Reply #43: 15 to 20 percent of the total tab. [View All]

[TahitiNut]

• Airport Porters - $1 per bag for normal sizes, $2 per bag for large or heavy items.
  
• Chauffeurs - 10 to 15 percent of fare.
  
• Coat Check - $2 to $5 upon retrieval.
  
• Concierges or Guest Services Representatives - $10 to $20 depending on the complexity of the service--theater tickets, restaurant reservations, tour bookings, last-minute arrangements.
  
• Hotel Door Persons - $2 for summoning a taxi by phone, $1 for hailing from street, $2 to $5 if they opened the door for you each time you entered and left the hotel.
  
• Hotel Porters - $1 to $2 per bag, $5 minimum.
  
• Housekeeping Staff - $2 to $5 per night, paid daily or as a sum at checkout.
  
• Parking Valets - $2 to $5 for parking and delivery.
  
• Restaurant and Bar Service - 15 to 20 percent of the total tab.
  
• Room Service - $5 minimum.
  
• Taxicabs and Hotel Courtesy Cars - 10 percent of fare, $2 to $5 minimum depending on service. Add $1 per bag placed in trunk.

http://www.ehow.com/how_112004_tip-properly-north.html

I've traveled extensively, worked in restaurants, and have a close nephew who manages a restaurant and I subscribe to the guide above. Furthermore, I never put the tip on a charge card - always in cash.