When we started logging 42h runs, most people were convinced they were "above average" with their phone use. The battery curves disagreed. Even in a self‑selected group of motivated users, the median time between charges was under 10 hours.

What a typical 42h attempt looks like

The classic pattern: a slow, lazy slope through the workday; a small dip on the commute; then a cliff somewhere between 21:00 and 01:00 when social feeds and videos take over. Almost nobody "just checks one thing" — the green line tells the truth.

Once participants tried to stretch to 42 hours on a single charge, two things happened: they opened their phone less, and when they did, they stayed for shorter bursts. Nothing in the OS changed — only the constraint did.

Why a line works better than a lecture

Screen‑time apps tend to explain your behaviour after the fact. 42h does the opposite: a single, bright line that quietly reminds you that the battery is finite. You don’t need a push notification; you can feel it in your pocket.

Run your own 42h →