Build a habit tracker whose core product is a portable, versioned ledger rather than a device-local interface. Every change would carry visible synchronization status, conflict resolution, recoverable history, and automatic backups, with import tools for common habit trackers. The initial product should cover phones and the web before adding watches, widgets, and broader health integrations.

Consumers increasingly track the same routines through phones, computers, watches, and health platforms, making device-bound records fragile. The evidence also shows that users already pay for habit products but will leave when synchronization or recovery cannot be trusted.