- Know where the spare key is hidden.
- Find the snoring of the other inhabitant(s) soothing, when and if you notice. Rarely notice it.
- Turn on the oven before you turn on the burners, without giving it a second thought, because the only way the burners light is if you have the oven on. Refuse to think this is odd.
- Negotiate a path through the house including several flights of stairs (of varying steepocity and widthiness) when extremely drunk and/or with your eyes closed.
- Fall backwards into your favorite spot on the couch on the first try.
- Bring home leftovers knowing they will be eaten by someone else in the family. Specifically try to have leftovers so you can bring them home for them.
- Avoid the squeaky parts of the stairs every time.
- By cough and the length of their strides be able to discern who is awake and what mood they're in.
Just a sampling. How do you recognize your parents' home(s)?