Use year isn't really important to us hasn't really been important to us, as we've never had to cancel a reservation, so we've never lost our points... we just keep track of our points, when & how we've used them...
Home resort IS VERY IMPORTANT & don't let any salesperson tell you differently... If you have a resort that you want to stay at MOST often, buy there, if you want to stay ONSITE most often, buy ONSITE... it is true, that at seven months you can change to any Disney resort, but that may lock you out of important DVC times when the DVC resorts are typically full...
VERY IMPORTANT. You can book rooms at your home resort 11 months in advance of your checkout date. At all other resorts, you have to wait until 7 months away. The 11-month window is very important because if you book at 11 months out, you should always get the room size and dates that you want.
Not that important. It is only important if you have to cancel within 30 days of your trip. So, if you plan to vacation at a specific time every year, it could be a problem. For example, if you want to go to WDW every November, a December use year would not be good for you.