Is one required to seek permission when entering one's parents' house, which one frequents often, knowing their consent and fearing to disturb them with repeated requests for permission?

A Muslim must seek permission before entering any house other than his own, even if it belongs to his parents, due to the generality of the verse: "O you who have believed, do not enter houses other than your own houses until you ascertain familiarity and greet their occupants" [Quran 24:27]. This is also based on the Prophet Muhammad's (peace be upon him) response to a man who asked him, "Should I seek permission to enter upon my mother?" He said, "Yes." This is so that he does not see them in a state they dislike or that he is not permitted to see them in.