Wow, I can't believe my littlest one is 3 months old this week!
I've always taken photos of both boys each week with a sign showing their age. This is a great way to document your little one's growth, and not have to wonder when that photo was taken, if your pictures end up mixed up in a box and you forgot to write on the backs. (or in this day and age, digitally dumped into an unorganized folder in your computer!)
Of course, I got this from my mom, who did the same thing for all three of us kids growing up! It's fun to go back and see where the growth spurts were, and to compare my two boys at the same age to see their similarities and differences!
Do you have any photo taking rituals with your kids? I know some people like to take a photo each week with a toy or stuffed animal, which helps show baby's scale in relation to something that doesn't change. When our dog was a puppy we took a photo each month of him sitting in my lap, until he was so big you could barely see me! ;-)