There are a few reasons to do your Christmas shopping in December, like the sales, and the feeling of being part of the holiday season. But if those aren't important to you, like if you already have sources to get things at great prices, and you really don't relish the experience of being in crowded stores, then it really doesn't matter whether you do your shopping in November or December. In fact, November has a lot of advantages: no sense of rush, less crowds, first dibs on picking from people's wishlists, and the chance to focus on other things as the holidays get closer.
That's why I always budget to start our Christmas shopping at the beginning of November, and usually by then, I've got lists of ideas for everyone that I've been accumulating all year long (whenever an idea occurs to me, in fact). Usually I'm done before Thanksgiving. And this year I'm almost but not quite done. I've gotten stuff for everyone on my list, except I still have a few things left to get for Siobhan, some more of the smaller, more frivolous things.
Yesterday while grocery shopping at CostCo I picked up a few of those. The fun thing is, Siobhan was shopping with me, so I had them in a grocery bag in the cart, and I put the whole bag onto the check out. The cashier was very amused at the situation, and enjoyed being party to this subterfuge; she rang up those items without taking them out of the bag, then slipped both the bag and later the receipt directly to me. (She was particularly tickled that Siobhan's credit card was the one being used to ring up the sale... though of course our cards go on the same account, so it's not like that matters.)
Years ago, we used to do a lot of our Christmas shopping this way, but nowadays we do most of it online. Now that I've exhausted the local stores, I'll probably go back to shopping online for the rest of my orders for Siobhan. I'll have to browse around for ideas, though. Nothing else on my list (or hers) seems right.