Did you have a doorframe height chart when you were growing up?
There are many childhood traditions that parents really look forward to doing with their kids. They remember how important these moments were for them as children, and they want to ensure their own kids get to experience that excitement as well. Who here doesn't remember the first Christmas they got to sit on Santa's lap at the mall, or the first time they got to go to the beach with their parents? These moments are special, and you carry them with you for as long as you can, at least until you get to create these memories for your kids as well.
Marking your height at the doorframe every few months and getting to see how much you've grown every time you enter your bedroom is also a tradition many kids cherish, and many adults think back to fondly. Every time a family moves, the one thing they always hate to leave behind is that little chart that shows how much the family has grown and evolved. When first-time parents hold their newborn babies for the first time, they can't help but think about the new adventures to come. That little growth chart at home is the perfect manifestation of that.