A child’s outgrown shoes measure change more concretely than a birthday does.

Dates are agreed and growth is physical. A birthday states a number; shoes that no longer fit say something undeniable happened while you were busy with ordinary weeks, which is why parents get ambushed by a shoebox rather than by a candle. Change is easiest to see in what it leaves behind. The body keeps a better calendar than the diary does.

Keep one small marker of the current size: a photograph in a doorway, a pencil line, the shoes. Look at last year’s version now and then. It is a way of noticing time while it is still passing.