I am not sure what one means when they say they tip a percentage on a cruise. The recommended tips are so much per person per day. This applies to all passengers and not just adults. Kids often required more care than the adults do. The amount of tip is up to the individual but if the person has worked and earned his suggested tip then you should provide it. If they have done very well then you should tip more etc. You concious is your only true guide. Also understand that the average 'stiff' rate is around 18% which is very embarassing for us as a group.