How many days

A large proportion of cruises are 7 days, because this fits well into most work people's vacation schedules and most people's budgets. That said, there are many options.

3-day weekenders: These are popular as a modestly-priced vacation or mini-break. Since these require little time off work, weekender cruises tend to have a younger demographic, including both couples and young families. As a result, these are lively and often party-oriented. These are usually only offered by mass-market cruise lines like Royal Caribbean and Carnival, though higher-end lines occasionally offer short repositioning cruises (see below).

4-day mid-week: If you can cruise mid-week, these can actually be cheaper than the 3-day weekend cruises. Guests are typically retired, especially outside school holidays. These are usually only offered by mass-market cruise lines like Royal Caribbean and Carnival, though higher-end lines occasionally offer short repositioning cruises (see below).

1-4 day repositioning cruises: Unlike the regularly-scheduled short cruises, short repositioning cruises are occasional events that occur when a ship repositions (e.g., on the way to Alaska for the summer). These cruises are a good way to "test" a cruise line (or cruising in general) to see if it appeals to you. They are usually a good value, but will need to buy at least one one-way flight; these cruises are never round-trip.

5-day: A few cruise lines are now experimenting with 5-day cruises. These seem to cater to working-age people who want to take a week off work, and have a day on either end to travel to and from the port.

7-day: This is by far the most common itinerary, as it fits best into working people's vacation schedules and most people's budgets. In general there will be a wide range of ships to choose from, including the very newest ships.

8 to 14-day: This duration is popular especially in Europe and more exotic locales where there is a lot to see, and a lengthy flight from the US warrants more time at the destination. Sometimes two 7-day cruises can be combined to form one 14-day cruise.

More than two weeks: Longer cruises appeal to guests who have both money and time. A long voyage by ship can be a relaxing and leisurely way to see the world. The extreme example is the 100+ day around-the-world itinerary now offered by several upscale cruise lines.