Use year has no impact on when you can go (anytime) or when you can call to reserve (always 11 months in advance at home resort and 7 at others).
The only issue with use year is whether you can bank points if you have to cancel. The new rule will be that you can bank all your points up to the eigth month of your use year but none thereafter. Thus, assume a September use year and you have a ressie for Aug 08 that uses points issued in Sep 07. Now assume, you learn in June 08 you have to cancel. Since you are beyond your eigth month of the use year, you cannot bank the points you used for that Aug ressie and must use them before they expire by Aug 31, 2008.
Now assume your use year in the above situation is March and you have a ressie in Aug 08 that uses points issued in March 08 and you learn you have to cancel in June. You can now bank all points into the next use year, Mar 09 to Mar 10.
Thus, if you generally go the same time of year, having a use year that begins 8 or fewer months before that regular time of year means if you cancel you can easily bank but having it 9 to 11 months before raises the problem if you have to cancel.
There is no other reason to be concerned about use year. Moreover, if you go at varying times of the year, it is also not going to make a difference.
