Like most kids nowadays, my children's lives are well-documented. One thing I used to do was to compare photos of the kids around the same age, wearing the same clothing or costume, or sitting in the same seat.
My favorite photos are the ones with the kids together. Every few weeks, I change the wallpaper on my phone to use the latest photo of the kids hamming it up together.
The only time I ever print out photos is when I send a printed holiday newsletter at the end of the year to family and friends who aren't on Facebook. As you can imagine, it's less than 20 families now.
Are you photographing your kids daily? What do you do with the photos afterwards?