reason #3 Why Not to Buy a Timeshare

Ability to exchange

Though exchange is an attractive reason for purchasing a timeshare, your "trading power" and the trade opportunities available to you, will depend on what you buy. Read more about how the timeshare exchange system works.
There is also a cost consideration here - if you're buying a timeshare for exchange ability, you'll want to pay close attention to these as well. Most exchange companies have annual membership fees + exchange fees involved when you actually do the exchange. There might also be fees for allowing someone else to use your unit.