Emily Post

RESTAURANTS:

15-20%, pre-tax

10%, pre-tax

No obligation for greeting you and showing you to your table.
$10-$20 for going above and beyond to find you a table on a busy night or on occasion, if you are a regular patron

No obligation
10% for extra service (curb delivery) or a large, complicated order

$1-2 per drink or 15-20% of the tab

No obligation
Tip occasionally if your server or barista provides a little something extra or if you are a regular customer.

$0.50-$3, depending on the level of service

$2-$5
Tip when the car is returned to you.

TRAVEL:

$2 first bag, $1 per additional bag

A smile and a "thanks" when he  opens the door
$1-$4 for carrying luggage
$1-$2 for hailing cab (add an extra $1 if it's raining)
$1-$4 beyond the call of duty

$2 first bag, $1 per additional bag
$2-3 for each additional service, such as room delivery

$2-$5 per day, left daily with a note marked "Housekeeping - Thank you"

No obligation for answering questions
$5-10 for tickets or restaurant reservations
$15 for hard-to-get tickets or reservations, or 10-20% of the ticket price

15-20% of the fare, but minimally $1
$2 for the first bag, $1 for the second

SALON/SPA:

15-20%, ask to be split among those who served you

15-20%

15-20%