This is why I usually do it yearly
Thus why I usually do it every Christmas vacation, but I couldn't in
2007 - my mom died, and I had to catch up with all I left behind because I was gone all of November
2008 - I'm sure there was a good reason (Maybe looking at my photos will give me a clue :))
2009 - I could not sit up due to my back going out on December 18.
2010 - So far, I did two years of Christmas photos end of 2006 (I had done through Gingerbread houses) and 2007.