Spreade out the expenses
When you make *ALL* your purchases in December(some people a cpl days before Christmas), this can decrease your finances. Instead, when you spread out the cost over the whole year, you will take less of a hit.
The reality is, you never know what expenses you will have in December. What if something happens(either to your car or whatever financial situation that could happen) that will seriously lower the amount of money you have to spend on Christmas presents. So buying throughout the year, instead of all at once, ensures you won’t be caught unprepared.