For the most part, Royal Caribbean ships that sail from the United States attract a wide variety of North American passengers, mostly between the ages of 30 and 55 on the seven-night and shorter cruises, and 50 and over on cruises longer than seven nights. Seven-night and shorter cruises are also popular with families, especially during American school vacation periods, when the ships will often be at filled at well past double capacity and carrying more than a thousand kids.

Cruises from the U.K. -- as well as Mediterranean, Asia and Australia cruises -- attract a significant number of locals from each area, as well as Royal Caribbean's usual North Americans.

Royal Caribbean's dress code is casual during the day; at night there's either casual, smart-casual or formal dress code depending on the schedule. Casual attire includes jeans and collared shirts for men and sundresses or pants with blouses for women; smart-casual means collared shirts, dresses, skirts and blouses, or pantsuits; and on formal nights, suits and ties, tuxedos, cocktail dresses or evening gowns are expected. If you want to avoid dressing up altogether on any night, the extensive Windjammer Cafe is always casual dress.

Caps, tank tops and bathing suits are never allowed in the main dining room or specialty restaurants; shorts are not permitted during dinner and footwear is always required.

No. Royal Caribbean ships really vary in terms of complimentary dining, with the main dining room and huge Windjammer Cafe as constants. Coffee, tea, milk, lemonade and a few other beverages are available without cost at all times, as well. Most specialty restaurants carry an additional charge, but there are options that are free, including pizza, the Boardwalk Dog House, the Park Cafe (on select ships) and more, depending on the ship. Ice cream, scooped at mealtimes and from machines in between (apart from Ben & Jerry's) is also free. Other dining choices with additional cost run the gamut from Asian to a steakhouse, deli and Mexican and Italian restaurants. Room service carries a $7.95 cost per order, with the exception of Continental breakfast.

The main pool areas are a magnet onboard any Royal Caribbean ship, as is the peaceful adults-only Solarium. Cruisers line up for the most adrenaline-pumping activities, whether to surf the FlowRider or try out new experiences from simulated skydiving and ice skating to bumper cars and escape rooms.

Broadway shows (on the ships that have them) are also quite popular and fill up any night they're on offer. Equally as in demand are the high-flying and diving acrobatics of the AquaTheater and the ice-skating shows on the Freedom- and Voyager-class ships.

Best for: Groups, couples and families who like (very) big ships with a vast amount of entertainment, day and night

Not for: Those who are after a quiet, intimate, small-ship experience; gourmands; couples avoiding kids