Last Christmas I spread out purchases and bought far too early (bargains picked up throughout the year), stuffed it all under the bed in the spare room, and promptly forgot what I bought people. I started off smug but by Xmas had far too much stuff stored up (which I've since farmed out as birthday presents for others during the year so not a complete waste), duplicate presents, etc. DD then decided she wanted something different come December than her September request, Gah! Plus I then got caught up in the Christmas shopping atmosphere / hysteria and bought loads more! I suspect my bargain hunting seriously backfired into a huge bill.
This year I am determined to be able to hoover under the bed until November but am already itching to buy stuff. What if they get sold out? etc . What do you do?