My mom didn't defrost the freezer for ages. It's finally dead, but it took 2 hours just for the doors to unfreeze from the rest so I could open them.
See for yourself:
It still technically works, it's just that the door doesn't close properly, making it kinda useless. It was only shut off due to high temp alarm, which I am surprised took so long to turn on as there was some gap in the doors all the time.