Sandi's reply was very precise. If you will not be using you 2009 UY points before the end of July 2009, you will need to bank them (if not done so already). Accordingly, when you decide to book your August 2010 vacation, you will first use those banked points, then start to use your August 2010 UY. Since your August 2010 vacation will already be inside your 2010 UY, you will be able to use the August 2010 UY points, without having had a need to bank or borrow the 2010 UY points. Thereafter, if you do not use all of your 2010 UY points, you will still have to decide as to if / when to ultimately bank the REMAINDER of your 2010 UY points ... especially if you will not be using them prior to the end of July 2011.