PSA – 9-volt Batteries
This is not door-related, but consider it a public service announcement that shows how much I care about you. I don't know how common this is, but I did confirm that a 9-volt battery can be used to start a fire and improper storage has led to several residential fires. If we proactively replace our smoke detector batteries and store the partially-used batteries until they are recycled, we need to take precautions to avoid the situation in the video below.