As others have said, if I'm wearing pants, I have a gun. If I'm not wearing pants, I'm probably in bed, and there's one in the nightstand.
It only takes seconds to be surprised wherever you are. I live in a safe neighborhood, but that's just a matter of relativity. Nowhere is 100% safe this side of the grave.
If the unthinkable did ever happen, and that door did fly open, being caught unprepared is not an option. Being prepared to defend my family is one of my primary responsibilities as a husband and father. Since I am not psychic, that means being prepared ALL the time.