Taxi Driver: Ten to 15 percent. Add an extra dollar or two if he helps with the bags.
Airport Porter: Most porters charge $2 for the first bag. If they don’t, you should pay at least that. Add a dollar or two for good service.
Other Airport Staff (Ticket Agents, Fight Attendants): Don’t tip them. It can be tempting to slip an agent a $20 bill in the hopes that you’ll get better treatment out of the deal, but that comes off as smarmy.
Bellhop: $2 for the first bag, $1 a bag after that.
Housekeeping: $2 to $5 a day. Leave this tip daily, as you often have a different person cleaning your room each day. (Leave a note so the housekeeper knows the money is for her.)
Concierge: $5 to $10 every time she helps you with something above and beyond the job description, like scoring hard-to-get tickets to a show.