People who have cruised before know a little secret: At the end of your cruise, the cruise lines offer incentives on board to sign up for your next cruise.

To get a better handle on how this all works, on my recent cruise on Ruby Princess I interviewed the ship's Future Cruise Consultant, Catherine Fullarton of Melbourne, Australia. 

Catherine's task is simple enough: to help passengers plan and book their next Princess cruise. But given Princess Cruises' extraordinary range of itineraries, many guests aren't quite sure what kind of sailing to choose.

"Some people come in and have no idea where they want to go," she says. So she helps them review brochures and discuss bucket list vacations like visiting Machu Picchu or the Great Wall of China.

Some of the more popular getaways include South America, Northern Europe, the Baltic Sea, Mediterranean and the Arctic. On European itineraries, “you can be in a different country every day,” she says.

One of the more eye-popping destinations is St. Petersburg, Russia. "You can spend two days in St. Petersburg, visit Catherine’s Palace, the Hermitage," she says. "It's amazing."

Courtesy of Princess CruisesWhen guests visit Denali National Park, Denali Princess Wilderness Lodge is the most convenient place to stay. The entrance to the park is less than a mile from the lodge.

Princess fame for its Alaska vacations

Catherine points out that Princess is best known for its cruises to Alaska — the cruise line now has seven ships sailing there. A lot of travelers opt for a land and sea vacation, or cruise tour, including stops at one of Princess's wilderness lodges. 

On a cruise tour, a popular itinerary takes yon on a flight to Vancouver, and then you sail along the Inside Passage, with stops at Ketchikan, Skagway, Juneau and Glacier Bay. "The captain actually takes the ship right up to Margerie Glacier, so close that you can actually hear the cracking of the ice and watch it calve into the ocean."

There's a financial incentive for guests to sign up for their next cruise while still on board. Under Princess's Future Cruise Incentive Program, if you put down a $100 deposit per person, you get $100 onboard spending money. If you’re not ready to book a specific cruise, you have two years to decide which Princess itinerary to choose, and if you don’t book, you get a full refund, she says. 

Say hi to Catherine if you spot her on Ruby Princess or her new assignment: She'll be joining Grand Princess any day now.