I've been at it for a couple of months now (even have some already wrapped). I have kids, niece, nephew, all that good stuff, so it either starts early. I also highly prefer taking the more relaxed approach and not having to deal with the crowds, so 95% of the "shopping" is online.
I have a think in August, start buying late September, finished about a couple of weeks ago.
Down side is someone'e gotten a present I got them for themselves.
Up side, I don't deal with stress, both shopping, and having enough money over xmas. The latter which is the reason why I do it now, even if it happened 10 years ago and I make okay money now to not worry about this.
I've bought for my mother, and the siblings I'll buy for, then a couple of sweet tins for the people I know, wrapping paper and sellotape, I have some cash set aside if Gaf secret santa happens, done.
I don't buy the usual Holidays sweets here (Polvorones / turrón) until at least December.
Regarding gifts, I don't have a lot to buy. I'm staying in Thailand for most of December and the first of January, so I will try to find stuff for the family there.