Cruising is one of the more convenient ways to travel. Yes, you're stuck on a boat between shore visits, but most modern vessels are a cross between a theme park and a Las Vegas resort. You can hardly compare them to a cramped car, an airplane cabin or even a fully stocked recreational vehicle.

Having meals, activities and entertainment prepared and ready at your fingertips can certainly make for a carefree vacation. Cruise packages range from quick weekend getaways to weeklong or 10-day island-hopping excursions. Longer ventures might circle an entire region over the course of a few weeks or months. Then there are around-the-world cruises that can last for the better part of a year.

But for those who want more, there are ways to live long-term on a cruise ship.

The growing trend of never-ending cruises

Last year, the New York Times and Conde Nast Traveler profiled a semi-retired investment manager named "Super" Mario Salcedo, who has spent the past two decades living on a cruise ship. The Times reported that others had retired in a similar fashion, spending a decade or more at sea. The paper estimated that the average cost of a 20-year retirement for someone leaving work at 65 is similar to the cost of two decades of continuous cruising.

Luxury cruise line Crystal Cruises has noticed. The company plans on offering long-term leases — for 40 years — for staterooms on their new vessels. The suites will likely be in the multimillion-dollar range.

Not all cruise companies require long-term leases for continuous passengers. Some cater to people who want to cruise on a budget. Investing site the Motley Fool found that regularly priced cruises, without all the frills, cost about $100 per day. Even after factoring in extra expenses such as rent for an onshore storage facility, an endless cruise experience would be several thousand dollars less than a year in an average assisted living home.

Of course, there are some very big differences, and it's the level of care someone requires that's the key. Nursing homes offer assistance with basic tasks like bathing and taking medications, and those services aren't available on a cruise. Assisted living facilities provide meals, entertainment, social gathering opportunities and housekeeping, many of the same services as cruise ships. Plus, on cruise ships, travelers get the bonus of sailing the world or spending the whole year in the tropics. Again, that's assuming we're talking about a healthy individual, not someone who needs round-the-clock care.

Onboard and on-shore activities and group meals give cruisers the chance to meet new people and socialize. This is an important element for retirement communities as well, but residents may not have the same level of stimulation as cruisers when it comes to visiting new places, trying new activities and constantly meeting new faces.

A survey by Cruise Critic found that 27 percent of cruise-goers would consider retiring on a ship indefinitely, and 32 percent would consider doing this for a couple of years before returning to land.

Snowbirding

Cruise ship at sunset It's a choice for some: An assisted living home, or this? (Photo: Romolo Tavani/Shutterstock)

According to CNBC, more "snowbirds" — people who live in four-season climates but spend wintertime in warmer weather — are cruising instead of spending time in traditional winter escapes like Arizona and Florida. The same "cheaper than a home, condo or hotel" dynamic applies to these winter refugees as well.

The industry is taking notice. Oceania cruises has a two-month-plus option called "Snowbird in Residence" that allows passengers to spend the winter sailing around the Caribbean. Other long-term cruises, provided by at least a dozen different companies in every price range, last for three to six months. These are usually marketed as “around the world” trips and are usually undertaken in segments. That enables wanna-be long-term cruisers to sample a segment or two before deciding to book an entire voyage.

Too good to be true?

As a higher percentage of the population reaches retirement age, residential cruising could offer an alternative to traditional assisted living for people who enjoy the onboard lifestyle. But there are drawbacks.

Cruise ship costs may vary if, for example, you're a single occupant in a larger cabin. Services like internet may cost extra. And you may need to have separate health insurance to cover international care and evacuation should you become ill.

Also, travelers need to be certain that they'll like the cruise lifestyle for the long term. Once booked, you're committed. Some cruisers enjoy meeting new people often and partaking in the same menu of activities, entertainment and attractions. For others, however, it could become monotonous.

Your retirement home could be a cruise ship
A trend toward spending your retirement on cruise ships may make more sense than you can imagine.