When you help another, you help the future you.

In my late twenties I gave up a rainy Saturday I badly wanted to keep to help my friend Julia move into a fourth-floor walk-up. I remember being quietly annoyed the whole day — the boxes were too heavy, the stairs were too narrow, the pizza she ordered was cold. I did it because you do it, but I logged it in some private ledger as a favor she owed me.

Twelve years later my marriage ended in a single, terrible weekend and I found myself needing to be out of my own apartment in seventy-two hours. I hadn't spoken to Julia in almost a year — life had drifted us — but I called her on some instinct. She was on my doorstep the next morning with a borrowed pickup, two friends I'd never met, a stack of flattened boxes, and a large pepperoni pizza still warm in its box.

'I remembered,' she said, when I tried to thank her. She stayed until the last light was out and the last box was in storage. Driving away that night I understood, finally, what I had done twelve years earlier. I had not lost a Saturday. I had put something small into an account I didn't know I was opening. When I finally needed to withdraw, the balance was exactly enough.