Some people here, Doc is one, I think, have different UY...we don't and even when we bought resale we went with our March UY.
If you buy the same UY, you can have all of the points in one contract so when you go on the
DVC member site, you can see all in one screen, I don't think that's the way it is with different UYs. If you have different UY's you could not book a night that combines both contract points without transferring points from one to the other, but you could book whole nights with each contract and have them linked.
If you're good about keeping different banking deadlines straight you may be better off buying a different UY with your different month travel plans. With our March UY, I do worry a bit about our travel in November, December and January, since those are outside the banking window.
We had placed a bid on a different UY, but backed out when it was rejected, the broker was surprised I didn't want to "negotiate" but between that time and the time I placed the offer, I decided not to get a different UY. I do not feel organized enough to make it work.
Bobbi
