Your stateroom host puts the tipping envelopes on your bed the night BEFORE your last night of the cruise. This gives you the next day to get to guest services to charge the tips to your room (you put the receipt in the envelopes for your servers/room steward). The tipped staff also accept cash. Most will gladly accept hugs

along with their monetary gratuity.
Remember, you don't need to tip (if you don't want to) at breakfasts and lunches because the tip you give your server covers ALL of the meals onboard (except for Palo). Most likely you will be served by someone elses servers at breakfast/lunch. If everyone tips their servers, they all are taken care of for all meals.
Here is my standard tip information:
What about gratuities? (September 2004)
We'll make it easy. It is customary to give gratuities in recognition of service, which you will most likely be treated to in abundance aboard the ship. As a guideline, may we suggest the following:
Per Guest per cruise______3-Night____4-Night____7-Night
......Dining Room Server___11.00______14.75______25.75
Dining Room Asst. Server____8.00______10.75______18.75
.Dining Room Head Server____2.75_______3.75_______6.50
..Stateroom Host/Hostess___10.75______14.50______25.25
Dining Manager Your Discretion
Room Service Your Discretion
For your convenience, a 15% gratuity is automatically added to bar, beverage, wine, and deck service tabs. All gratuities can be charged to your room charge.
At the Walt Disney World® Resort, 15% is the customary gratuity at restaurants and bars.
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So if there are 3 of you on a four night cruise your tips would be:
Server________3*14.75 = 44.25
Asst. Server__3*10.75 = 32.25
Head Server___3* 3.75 = 11.25
Stateroom_____3*14.50 = 43.50
________________Total: 131.25