Norwegian Epic in Miami
Photo: Norwegian Epic in Miami / NCL / Kikor

8. You won't get to try everything.

Some of Royal Caribbean and Norwegian’s largest ships have more than 20 dining venues — and almost as many lounges and bars — so it’s impossible to sample them all on a seven-night cruise. Do your research in advance and make a list of the places that you really want to hit, and make reservations for as many as you can as soon as you book your cruise. That guarantees you'll get to try your top picks and won't disembark disappointed.