I had an air con remote control that wasn't working at all. But at some point I noticed that when I turn on the air con manually and the room gets cooler, the remote control works as expected. I thought it can be caused by moisture inside the device and probably something happens with it when it is cold. I tried different batteries and it didn't change anything - the remote was operational only when it was cooler than 29 C (I live in a humid tropical country). I ended up keeping the remote in the fridge without understanding the real reason of the issue.
Now several years passed and my Xiaomi Mi Band 2 stopped working. After a lot of searching I found out that many people had the same problem and putting the device in the fridge fixes it. I tried it and amazingly, it worked!
What can be a reason of this behavior? Temperature, humidity or batteries?