Learned my lesson after a trip last week… I have sensors for nearly everything, but somehow totally forgot about the Fridge / Freezer.
A power outage made my fridge lose it’s mind and turn off cooling, even after it powered back up. Unplug / replug seems to have fixed it, but all the food was spoiled when we got home. Simple $10 temperature sensor could have saved everything!
Since I’ve started automating stuff I’ve got myself an Acurite wireless fridge and freezer thermometer (initially found out about it on Reddit, before it all went to shit and all). It both has a nice magnetic display and it transmits in 433MHz band, so a SDR dongle plugged into my Home Assistant machine can receive the temp readouts. So far it didn’t prevent any disasters, but at least I know how hot it needs to get for the fridge to start having trouble keeping cool.
I also went this route. I’ve definitely had better luck with the Acurite sensors than I’ve had with Zigbee/ZWave sensors in terms of update frequency.