My wife's been doing something similar, if far less extensive for us, actually: she takes identical portraits of the kids on their birthdays, and it's fascinating to see them grow up and change--and not. It's always a bit of a wrestle, though, to coax interesting, expressive photos out of squirmy/self-conscious/distracted kids.
So hats off to Dutch filmmaker/dad Frans Hofmeester, who has been shooting brief video portraits of his kids week in and week out for 12 and 9 years.
Because his big sister Lotte's video has been making the rounds, getting Internet-famous, I figured I'd try to give Vince's movie a plug. I can only imagine it can be a pain being the younger sibling.
Vince Time Lapse: Birth to 9 years in 2 min. by Frans Hofmeester [vimeo]
Oh I can't agree more with your statement that kids grow too fast, this is for sure. I remember when my nephew was just born and now he's already 7 yo, this is totally fascinating!