A world cruise has to be the ultimate holiday at sea – nearly four months away from home, being waited on hand and foot, as you circumnavigate the globe, visiting numerous exciting and exotic destinations along the way.

Round-the-world cruises sail east to west, through the Caribbean and Panama Canal, on to Australia and back through Asia, having saved the best for last. You can wave farewell to friends and family as you set off on your global jaunt from Southampton or Dover, or you can start your circumnavigation in the USA.

World cruises depart in January and arrive home in April or May, neatly avoiding the worst of the winter weather. Just think. While some friends and family shiver in the grey back home, you can be cruising the Caribbean, passing through the Pacific and basking under blue skies in Sydney.

Take your time
Unlike that most famous of circumnavigators, Phileas Fogg, you don’t have to go around the world in 80 days. Most world cruises take more than 100 days, during which time there will be plenty of days ashore, visiting places many people only dream of, such as Tahiti, Hawaii, Japan, Vietnam, Cambodia, Eastern Malaysia and New Zealand, and navigating through the canals – Suez and Panama – that changed the face of sailing by opening up new, and easier, routes for ships.

There will also be a lot of days at sea, particularly if your route crosses the Pacific – after all, it’s a long way around the world. It’s worth working out how many there actually are on your chosen itinerary as it’s not always immediately obvious from the way they are presented. If six days or more at sea doesn’t bother you, fine, but it can be disappointing if you want to see the world, rather than yet more water.

Most cruise lines lay on lectures and spa talks during days at sea, but it’s also a great chance to relax with a good book, have a spa treatment or head to the gym, exercising off all those snacks, teas and late-night bites. It’s easy enough to put on weight on a two-week cruise; even easier during four months at sea.

Long voyages
If time and money prevent you from going on a world cruise, don’t despair. Several cruise lines offer long voyages – both Fred Olsen and Holland America Line will be spending two months or more circumnavigating South America in 2010 – and you can also hitch a ride on a world cruise sector.

All cruise lines divide their world cruises into sectors of two weeks, a month, even two months, that can be booked as they come or added together to create your perfect cruise. As such, sectors are popular. Fred Olsen Cruise Lines says 37% of passengers do the whole thing, with the rest on sectors, while on P&O Cruises’ 1,870-passenger Aurora last year, 1,100 passengers were doing the full circumnavigation, which meant the rest were like me and dipping in and out of the itinerary.

You don’t have to be an experienced cruiser to book a long voyage, but it helps as committing yourself to almost four months at sea if you don’t know whether you’ll enjoy the experience is a big leap of faith.

Cruise virgins who fancy themselves as globetrotters should book two or three short cruises first, with a couple of different lines, so they not only find out if they like cruising, but also pin down their favourite cruise style. Some like the very British P&O Cruises, others the more cosmopolitan Princess and others the ultra luxury offered by a Crystal ship.

What to pack
Having chosen your preferred cruise, packing has to be the next most difficult task facing circumnavigators. You’ll need clothes for warm, cold and wet weather, as well as formal, semi-formal and smart casual evenings. And you’ll also need enough of all those different types of garments to last four months. If you’re not cruising from a port close to home and therefore have to fly, consider sending some luggage on ahead as you’ll be faced with the usual airline baggage restrictions which are incredibly limiting for such a long holiday.

Remember, also, that accessories are a wonderful way of giving clothes worn once a new lease of life, and don’t forget that all ships have a laundry – a paid-for service or a DIY version (ask if you need to take your own powder). Also, there’s always the option of replenishing your wardrobe as you sail the world – Asia especially has some great designer bargains to look out for.

And so to bed
Since you’re going to be at sea for several months, it really is worth splashing out on the biggest and best cabin you can afford as it will be your home for some time. It doesn’t have to be a suite, although that would be ideal, but consider booking a balcony, so you have somewhere to go for a spot of “me” time.

The usual rules apply when picking the cabin’s location. Lower rooms in the centre of the ship are the most stable, while those at the aft end take the brunt of the movement if there is a heavy swell. They do, however, have selling points of great views over the ship’s wake and often bigger balconies.

How much?
A world cruise doesn’t have to cost the earth, but if the budget allows, you can easily spend a fortune securing the best suite on a six-star line.

For 2010, P&O Cruises is offering a 94-night round-the-world voyage on Arcadia from around £8,400 per person, which works out at less than £90 a day for a room, all food and entertainment.

That’s really not much more than you would spend at home when you factor in the heating, electric and assortment of other bills, plus you can enjoy the added bonus of being waited on hand and foot.

At the other end of the spectrum, you can pay anything from £25,000/$50,000 to £120,000/$250,000 for a 108-day cruise around the world on Yachts of Seabourn’s ultra-luxury Seabourn Odyssey. For that you also get all drinks, gratuities and even some exclusive shore excursions included in the price. The choice is, quite simply, yours.

Top tips for booking your world cruise

Book as soon as possible
World cruises sell fast but if you get in early you’ll get the best prices and the cruise and cabin you want.

Book with your favourite cruise line
A long voyage is not the time to experiment with something new only to discover you’ve made a mistake.

If you don’t have the time and money
Book a sector rather than the whole cruise – these range from two weeks to a whole month or more.

Splash out on the biggest and best cabin you can afford
It will be your home for up to four months.

Book a balcony cabin
You can watch the scenery go by in private.

Count the sea days on the itinerary
Make sure you know what you’re booking –check how many days will be spent at sea, as well as which exotic ports you’ll be visiting.