We love our October use year because we like to travel in May, October or December. If we book in May and need to cancel, our October use year still allows us to bank those May vacation points.
We have a Sept UY because that's the contract I came across at BCV (resale) that was the right # of pts and right price. We travel at all different times of the year, so I would be hard pressed to have a "right" UY.
We have October, because I specifically requsted it when we bought. That seems to be the perfect UY for us because we usually travel to WDW in October or January. However, the right UY really depends on when you travel.
I would like to add on at HHI at some point, but will do that as a resale if and when that happens. Two reasons: 1) The cost. 2) I do not want an October UY for HHI and my understanding is that if you add on you will keep your current UY. If that is not true, please correct me.
I personally think people make too big of a deal about this issue, but if all things are equal and you have a choice, then I like Jan or Feb as that is when dues need to be paid.
In a strange sorta way, if I have to pay dues in Feb for a November use year and have to borrow those points, it seems weird.
Perhaps Disney should charge annual dues on a rotating calendar.