I usually start putting together the Calendars and Diaries in September and put them on this site for pre-order. They then ship worldwide the beginning of October.
I base the amount I order on the pre-orders. Last year I sold out a good three weeks before Christmas. Once I sell out that is the end of the calendar/Diary for another year as there is very little profit involved and I have to make sure they all sell to recoup my outlay.
With this in mind there is a mailing list for when they go on sale. If you are interested in either please consider adding yourself to the list through the contact page and don't leave ordering until the last minute. I hate disappointing people but I simply can't order more once they are gone because of the sheer cost of a small order and the time constraints involved.