I wouldn't spend too much time worrying about use year. As previously stated, unless you anticipate having to last-minute cancel trips, it really doesn't have an impact. When purchasing directly from Disney, they'll usually tell you what your use year is going to be, rather than asking you which one you want. Resale is the one place you can really pick and chose.
The other thing to keep in mind is that, depending on which resort you're purchasing, you'll be using the contract for the next 40-50 years. What makes perfect sense to the way you vacation today will most likely be quite different as time passes. For example, picking a use year based on traveling during kid's school vacations will change over time as your kids get out of school, and you decide it's better to vacation in the fall when prices are cheaper and temperatures are more comfortable.