Most will recommend picking a Use Year that is just before the months you usually will travel so should you need to cancel a reservation you would still be able to bank current UY points used in that reservation AND if any banked &/or borrowed points are part of that reservation you'd have some time to reuse these banked &/or borrowed pts before end of UY.
Use Years are February, March, April, June, August, September, October and December. January, May, July and November are NOT Use Years (so you would not be able to pick these months)
If you'll regularly be traveling in February and July then February is a good choice, banking deadline is September 30th and end of UY is January 31 so even cancelling a July trip will give you at least 6 months to end of UY.
If you think you may occasionally want to travel during December holidays time, then you might want to consider a December UY and this still covers you well for travel in February and July too. Dec UY banking deadline is July 31 and UY ends Nov 30.
Also, keep in mind that your UY month does not have any impact on when you can call MS to make a reservation : you may always reserve as early as 11 months before check in date you'd like at your Home Resort and as early as 7 months before at any other
DVC resort.
Best wishes