I can't give you advise on what the best month is since I am new to this too, I'm not really sure, but I can give you an example-My use year is October, and this is because my favorite week to go is the last week of Nov, since my birthday is 11/30 and it's all decorated for Christmas, and it isn't as crowded since it is after Thanksgiving and before Christmas. So, if you have a favorite time that you like to go, pick a month that is about a month ahead of that. Use year is important so you know when you have points available, and for banking or borrowing. But it won't stop you from going other times of the year-for exampple, I mentioned my favorite time to go, but I wanted to go twice so I'm also going in April.
I hope this helps!