Another newbie gratuities question-- we will be cruising on Azamara which includes gratuities in their pricing. However, do I assume correctly that additional tips may be prudent for, say housekeeping, butler and waitstaff? I know drinks carry an added 15% for gratuity and, of course spa treatment and other added services will entail adding on a tip.

Our cruise is 15 nights starting and ending in Amsterdam and cruising Norwegian fjords. What monetary unit should we plan to use for cash tips?