I take a lot of pictures. I noticed I take pictures of my daughter in the same place year after year. Then I realized, this was a good way to see how she grows.
The first time I noticed any difference in my daughter was when I put these 3 pictures side by side. I took a picture of her on Palm Sunday in 2009, 2010 and 2011. What a growth spurt. I am measuring by my son's picture in the background. Looks like she's grown at least a foot.
Every year so far from 3 months.