From 2018-2020, 37 new cruise ships will come online adding 99,895 guests to worldwide passenger capacity. However, all the cruise ships, filled to brim year-round, could not carry half the number of annual visitors to Las Vegas.
An Australian researcher compared the costs of a week-long P&O Pacific Islands cruise from Brisbane, with stop-offs such as Noumea and Lifou, to a similar land-based trip.
Using the ship as accommodation and transport, round-the-clock food and entertainment, the fare was NZ$1840. Adding in a drinks package, shopping and shore tours, the holiday totted up to NZ$3000.
Though it's not possible to replicate the cruise, the flights and the land-based accommodation, shuttles, food and drinks, entertainment shopping, and excursions cost around NZ$4530.
For newbie cruisers, the first decision is probably: what's the right type of holiday for us?
If you want to sail on an enormous floating hotel with pools, waterslides, restaurants and nightly shows, opt for an ocean cruise.
River cruising involves smaller ships with fewer passengers and less likelihood of seasickness. They mostly travel at night, reaching a new place every day, and offer more time to visit destinations.
If you're a solo traveller, look for a line offering single-occupancy cabins or waiving the solo supplement. Some facilitate cruise groups for solo travellers.
Family-friendly cruises offer programmes like kids' clubs to keep the offspring entertained, but if you're not keen to share your ship with the younger generation, several companies operate over-18-only cruises.
Luxury cruises offer VIP service, more refined dining and better amenities. If you're less keen on water slides and cabaret and more interested in nature-watching and remote villages, consider an adventure or expedition cruise.
It's often thought cruise passengers are more mature travellers, but the CLIA Global Passenger Report puts the average age at 46.7 years. The median age is between 60 and 69-year-olds, with 19 per cent younger than that.
As you might expect, short and close-to-home cruises attract a younger crew; longer itineraries and exotic destinations tend to attract an older set.
Coming on stream next year is a new cruise line: Richard Branson's Virgin Voyages will launch Scarlet Lady, with 2860 berths, the first of three identical ships on his adults-only "Vitamin Sea" concept, which focuses on passenger wellness, relaxation and fun. Read: an outdoor boxing ring, tattoo parlour and test kitchen. It'll sail the Caribbean out of Miami.
Meanwhile, Carnival's Mardi Gras will be the first of two vessels able to accommodate 6600 passengers, largest in the world by passenger capacity.
At 331m long with 2444 cabins, MSC Virtuosa will carry nearly 6300 passengers. Onboard entertainment includes a fine art museum, Cirque du Soleil show, a double-deck indoor amusement park and an outdoor water park.
P&O's Iona, carrying 5200 guests, will be the biggest ship built for the UK market and the first powered entirely by LNG.
Odyssey of the Seas will be Royal Caribbean's second Quantum Ultra Class vessel, a similar size but a step up in facilities and entertainment from the frequent visitor to our shores, Ovation of the Seas.
Princess Cruises' Golden Princess will be renamed Pacific Adventure and be transferred to P&O Cruises' Australian fleet. Celebrity Apex, sister ship to the Celebrity Edge, features the Magic Carpet, a moveable deck cantilevered off the side of the ship which rises from decks 2 to 16 and transforms into a bar, a restaurant and an extension of the embarkation area.
The golden rule for booking a cruise, is to get in early. While you're thinking about your 2020 holiday, veteran cruisers have probably snapped up the balcony cabins and are thinking about where they'll sail in 2021.
Apart from the classics – the Med, Alaska, the Caribbean, the Pacific - hot new destinations include Madagascar, Reunion, and Mauritius in the Indian Ocean, where you can visit lemur colonies and swim with manta rays and sharks.
Southeast Asia has become popular in the past few years; Viking's 15-day trip between Bangkok and Hong Kong offers overnight stays in five ports.
Europe's great waterways – the Danube, Rhine and Rhone – are favourite river cruises, but the Mekong is beginning to rival them in popularity, particularly with Kiwis.
Adventure or expedition cruises can take you to meet the giant tortoises and iguana of the Galapagos or in search of the polar bear in the Arctic. On this type of cruise, you're likely to be joined by a scientists who will help you learn from your trip.
Don't think that cruise lines are going to run out of new destinations anytime soon. Adam Armstrong, Australia-New Zealand managing director of Silversea Cruises, says his line takes its Classic (luxury ocean cruise) and Expedition (smaller, adventure) ships to 1084 ports and "for 2021 and early 2022 we've found another 26 that we haven't been to".
Itineraries include a return to the eastern Mediterranean - the Black Sea, Holy Land, Istanbul – off the books for a few years for security concerns.
"In northern Europe we're doing even more Iceland content because it's in such high demand. We're doing a full circumnavigation of Iceland, not just one or two ports, but almost a dozen in one itinerary."
Closer to home, Silversea is moving an Expedition ship from Europe to Australia's Kimberley region.
His hot tip: "I don't think many New Zealanders have been to the Subantarctic islands. We equate it to South Georgia and the traditional Antarctic route from South America - the wildlife and the scenery are absolutely amazing, but very few people go there."
