Unless you are on an all-inclusive ship, wine with dinner and drinks at the bar can really add up. It’s tempting to tuck a bottle of vodka or your favorite vintage into your suitcase along with your swimsuit and socks, but don’t expect it to be there when your bags arrive in your cabin. All checked baggage goes through X-ray machines, and liquor bottles rarely slip pass the sensors. Determined not to pay that markup on board? Cruisers have tried everything, to varying degrees of success, including filling mouthwash bottles with their spirit of choice to get past security

Heading off on vacation with your partner means the chance for some alone time. While overtly, um, amorous activities in public are frowned upon, the deck does clear out after midnight. So, if you were thinking of a late night nudge, nudge, wink, wink under the stars, you may find privacy. Not to spoil the mood, but remember that you are almost certainly on camera. Ships are loaded with them.

Only the most traditional lines still require that you pack ball gowns and tuxedos. Still, formal night is the main event of the entire cruise for some passengers on ships that have them. To those who like to dress up, the worst thing you could do on one of these sailings is to skip the penguin suit and constricting dress. We're not suggesting you — gasp! — leave the room in this dress-code denying attire. Just stay and and order room service and watch a movie in your cabin instead. You’ll still be considered a rebel ... in sweatpants.

Maybe you’ve been to Rome numerous times before and aren’t in the mood for the long transfer from Civitavecchia. Or maybe you’re just not interested in another day on the hot sand and would rather enjoy a cool day away from the Caribbean sun. Either way, waving off time on shore will elicit some strange looks from fellow passengers who can’t wait to experience the day’s port. While they are all scrambling to get off the ship, you can linger over breakfast and lounge by the pool without having to angle for the best lounge chair. Another bonus: cheaper spa treatments, since most ships offer a discount while in port. So book a massage, have the sauna to yourself, take a nap, and go to dinner completely relaxed.

Luxury ships and some river cruise lines stock their cabins with high-end products from brands that are considered a splurge (think Bulgari). You can even sometimes find full-size bottles that will last you the length of your cruise and then some, like the Etro products on the new Crystal Esprit. But maybe want more than just what’s left in the bottle to take home. Start by charming your cabin steward, gushing about how much you love the scent. They might just refresh them daily, sending you home with a suitcase full.