The Traveler's Journal

A pilgrim walked a thousand-mile journey. Each evening, he wrote in his journal: where he was, what he carried, which path he'd taken.

When bandits robbed him and left him lost, he didn't have to start from the beginning. He found his way to his last known position from the journal and continued from there.

The journal was small. The journey was long. The cost of writing was nothing compared to the cost of starting over.