Christmas Gifts vs Christmas Budget... why bother?

Every year I set aside x amount of money each month for Christmas gifts. I base it on the previous year's budget, add whatever amount I exceeded on that budget and add 5% for inflation. In theory by Christmas I will have plenty of money to buy gifts. Yeah, to date I've not had a year that works. I just added it up and I'm again over... this time by only $137 and change, but still...

Do you always overspend for Christmas?