As it says on the RCI website: Q: What are gratuity guidelines for cruises?
A: So that you can thank those who have made your cruise vacation better than you could have imagined, we've developed these gratuity guidelines:
Stateroom attendant: $3.50 USD a day per guest
Dining Room Waiter: $3.50 USD a day per guest
Assistant Waiter: $2.00 USD a day per guest
Headwaiter: $.75 USD a day per guest
Note: These gratuities apply to guests of all ages.
Gratuities for other service personnel are at your discretion. A 15% gratuity will automatically be added to your bar bill or wine check when you are served.
Envelopes for gratuities will be provided in your stateroom on the last night of the cruise. Gratuities may be paid in the following ways:
Pre paid by having them added to your reservation by your booking agent.
Added to your onboard SeaPass account.
Paid in cash at the end of the cruise
You dont have to pay gratuity up front it is down to your own descresition on the amount you wish to tip
You are expected to tip Stateroom attendant, Waiter, Head waiter and assistant waiter. I think they advise about 10 dollars per guest per day total, this can be added to your onboard account on the last day of the cruise.