What Actually Happens When You Leave an ESP32 Running 24/7

There is a small board on a shelf that never sleeps. No fan noise. No screen. Just a faint warmth if you press a finger against it long enough. The LED stopped blinking weeks ago. Or maybe it still is, and you stopped noticing. It's still running. And that's where people get it wrong. They think "running" means stable. Predictable. Done. It doesn't. It Doesn't Stay the Same Device The first version of your ESP32 is the one you flashed. Clean. Intentional. Every line of code accounted for. That version doesn't last. Over time, the device drifts. Not in some mystical sense. In a very literal accumulation of state. Buffers fill and empty. Memory fragments. WiFi reconnects hundreds of times. Timers tick past thresholds you never tested. Edge cases stop being edge cases because given enough hours, everything happens. You wrote logic assuming a day. Maybe a week. Leave it for a month and you're no longer running your code. You're running everything your code didn't anticipate. There's a diff