I am amazed at how concerned some people are about the way other people do things. I personally plan early but I don't spend my time making negative remarks about those who prefer to wait. Different things work for different people. I tend to assume people do what is best for their own family/situation.
Christmas planning tends to be an ongoing situation for me which kicks of to proper planning around August. The main reason being I hate August. My son is autistic and hates the summer holidays, he kicks of badly the whole of the six weeks. It is hard to go anywhere or do anything fun because of his behaviour and I am epileptic, if it is too hot I prefer not to risk going out in the sun alone with the kids (over heating causes seizures). The days are long and crap, in my free time I enjoy planning a more fun time of the year.
I buy presents all year round, as I mentioned my older son is autistic and my little one is heading towards a diagnosis in the next few months. They have set, specific interests and they can't ask for Christmas presents (severely speech delayed).
I know what they enjoy and they are a safe bet to buy fairly early on if the price is good. I have already brought some little things for next Christmas, a sticker book and a Take 'n' Play train. The money I save doing it that way means I am able to buy more quality presents than they will enjoy long term and less 'tat'.
They don't get any more presents due to me buying early, they each have eight toy presents and two books under the tree. That number is set and I don't go over it.
It works for me and for my family in general which is really the only thing that matters. As I said I assumed others do what they do because it works for them. Is that really so hard to understand?