Embedded devices without watchdog timers can hang indefinitely, forcing users to manually power cycle — a real-world failure the author experienced with a smart light switch. A watchdog timer is a hardware timer that resets the system if software fails to periodically signal it. Five best practices are covered: using an independent oscillator-driven watchdog, layering multiple watchdog tiers (including a 'phone home' timeout), setting realistic timeout values (2–3× longest task duration), implementing a task monitor pattern where all critical tasks must check in before the timer is pet, and logging reset reasons to non-volatile memory for field diagnostics.
