Not Honoring the Advice of Parents is Not a Sin
22-1-2019 | IslamWeb
Question:
If my parents tell me to do something which is culturally not regarded as not obeying parents or if they tell me something which is most likely to be a advice not a command, is it then allowed to me to do sonething else?For example my mother told me to put the heater in my room on level 2 when I go sleeping. But this was I think an advice because if I would use it on level 1 or 3 or 4 the would not say something. Or if she told me weeks ago "go to sleep early". If I would go to her and would say "can I stay up long" that would be very strange because 100% she would say something like yes and think why is he asking me such a strange question.
Answer:
All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad 
is His slave and Messenger.
Whenever children can obey their parents in what does not constitute disobedience to Allah, then they should obey them and do what they request them to do. By doing so, they (children) will earn the love and pleasure or their parents, and consequently Allah will be pleased with them (the children).
Abdullaah ibn ‘Amr 
narrated that the Prophet said: “The Pleasure of The Lord is in the pleasure of the parents and the anger of The Lord is in the anger of the parents.” [At-Tirmithi]
Sometimes it may be difficult to determine what the parents exactly request from the children, whether it is only an advice or an order.
If it becomes clear for the child that what the parents said is only an advice (and guidance), then he is not obliged to obey them, and he is not considered as being undutiful to them by not doing it.
Al-Aloosi 
said in his Tafseer Rooh Al-Ma’aani, quoting from Al-Balqeeni:
“In regard to not adhering to the command or prohibition from the parents in matters that do not cause any harm at all to the child, and it is just an advice to him, then it is not considered as being undutiful to them.” [End of quote]
For more benefit on the limits of obedience to the parents, please refer to Fatwa 84942.
Allah knows best.