bookmark this:
http://www.disboards.com/threads/understanding-use-year-updated-april-27-2016.1942668/
don't think of use year as when you "get" the points. instead, think of use year as the 12 month period when you can use the pts for a stay.
for your dec 2016 UY, your pts are valid for a stay from dec 1, 2016 through nov 30, 2017.
if you don't want to stay during that period, you can bank those pts forward and they would THEN be valid for a stay from dec 1, 2017 through nov 30, 2018.
(keep in mind also that you can only move pts with banking or borrowing ONE TIME. after that, they will expire if you don't complete a stay by the end of that use year.)
a feb 2017 stay falls within the dates for your 2016 UY (dec 1, 2016 through nov 30, 2017.) so you could call as early as march 2016 to book your home resort for feb 2017 using those current 2016 UY pts. if those are not enough, you would have the option to borrow 2017 UY pts to complete that stay within your 2016 UY. (and you could borrow from 2017 if you called in march 2016 - just to be clear.)
if you bank your 2016 UY pts forward but decide later to stay in your 2016 UY, you would still have the option of borrowing from 2017 - but that is not a great plan. if you cancel the feb 2017 trip more than 30 days out, your 2016 pts drop back into your 2016 UY and you still have the option to bank them later (by the end of July 2017) if you choose. like i said above, if you borrow and cancel, you cannot move the pts again and have fewer options.
generally, banking is something you can choose to do if you don't plan to make a reservation. but you don't borrow pts unless you actually need them to complete a reservation.
but the linked thread is a great, great resource.