1My house was originally built with a breezeway with sliding glass doors at either end between the garage and the house itself, with the front door of the house and the people door to the garage opening onto the breezeway. A few years ago, I had the breezeway remodelled into two small rooms, with actual walls and doors on the ends instead of the sliding glass doors. The back half has a dog door opening onto the fenced backyard and serves as the dogs' shelter from inclement weather when I'm not home; the front half has a real front door for the house and serves as a mud room, non-climate-controlled storage, and most importantly, an "air lock" ensuring that there are two normally-closed doors between the areas where the dogs are supposed to be and the unfenced outdoors.
2This triggers some dim memories of one of my neighbors helpfully "fixing" the door, which wasn't latching securely. Post-"fix", in some weather the door actually worked OK, but most of the time it's been tight against the door frame and the deadbolt is hard to operate.
3This seems counter-intuitive; tightening the top hinge should make the door ride higher. But I'm not going to argue with or try to analyze the reality on the ground (or in the wall in this case), that with the hinge screws tightened, the tongues of both deadbolt and latch were hitting the metal on the bottoms of their respective strike plates instead of fitting into the holes.