Related: Carnival Cruise Line passengers share special celebration tips. Some of these optional extras seem like cruise essentials to some passengers, but their costs can make cru

On Royal Caribbean’s ships, Starbucks drinks are not included in any drink package, while hand-crafted beverages from Café Promenade (which use Starbucks coffee) are. Plus, the beverages sold at Starbucks are significantly more expensive than comparable drinks served at the alternative.

And for those who want to celebrate their special day with family and friends, a cruise can be the ultimate birthday party. Even if you don’t want a party, there are plenty of ways to treat yourself on a birthday cruise — from pampering yourself at the spa and indulging in a specialty dining experience to embarking on a bucket-list shore excursion.