There is a pre-paid service fee aboard the Norwegian Epic cruise ship that each guest is required to pay. That fee is a charge of $12.00 per person per day. It is up to each individual traveler whether or not they wish to further tip other wait staff providing services. For those guests receiving individual attention for a particular service, such as receiving an alcoholic beverage or a spa service, it is recommended to tip approximately 15 percent.
For more info, see our feature Norwegian Epic Cruise Ship