There are, of course, other factors that you should consider beside the numbers. For starters, some people who bought timeshares during the past ten years have not seen a 5 percent per year rise in lodging costs in the locations where their units are based. In 2001 and 2002, for example, the monitoring company Ernst & Young reported 1 and 2 percent declines in the average rates of hotel rooms. This means that anyone who bought a timeshare before or during those years likely would have paid about the same amount, or less, for hotel rooms during that time period versus a timeshare.

Also, you must consider whether you actually believe you will keep — and use — your timeshare unit for twenty or thirty years. Timeshares, because of their high front-end costs, typically do not tend to become good bargains until they have been used for some time. If you buy a $20,000 timeshare unit at 15 percent financing and use it for only two years before selling it, you are going to have paid a heck of a lot more for two weeks of vacation time than you would have by just staying in hotels instead.

Another factor is miscellaneous fees that you will be required to pay during your decades-long period of timeshare use. For starters, if you finance your purchase, you will have interest payments. These are typically higher than first-home mortgage payments, as timeshare developers set the interest rates themselves, sometimes in the neighborhood of 15 percent or even more.

You also have to factor in your timeshare unit's annual maintenance fees, which typically average from $200 to $600 per year. That may sound high, but when you compare those numbers with having to maintain your own vacation home year-round, the timeshare maintenance fees are nominal.

There are also special assessment fees that you will be required to pay from time to time, for things like major beachfront upgrades, golf course work, and the like. And don't forget those exchange fees that you read about in Chapter 1. As of late 2005, they were in the neighborhood of $125 per exchange.

Many of these fees and surcharges, of course, will rise along with inflation over the years, just as hotel prices are likely to rise. In some cases, you will come out ahead by owning a timeshare. But in other cases, you might not.

If you simply want to return to the same home resort year after year, and if you can get a good deal on a timeshare unit that you absolutely love, buying it may be a no-brainer. After all, buying a timeshare is, in part, an investment in the quality of vacations you hope to enjoy for many years to come.

That is also true if you want to exchange your timeshare unit for others: Your exchange company's rating system will give you some peace of mind about the quality of vacation and resort you will enjoy no matter where in the world you decide to go. Economically speaking, though, if you intend to make a lot of timeshare exchanges based on the long-term financing of a unit that you buy today, then your overall financial benefits will depend on several factors: how often you vacation, how much you tend to spend on lodging, whether you choose a high-priced area for your home resort, and what type of timeshare you buy.