When should a father oblige his daughters to wear the legitimate dress (hijab), and at what age?

A father is obliged to command his daughters to wear the lawful attire (hijab) when signs of femininity appear on them. It has been said that this is at seven years of age, and it has also been said at ten years of age. The matter varies from one society to another, provided that the age does not exceed ten years. The Prophet, peace and blessings be upon him, clarified the importance of educating children in the hadith: "Teach your children to pray when they are seven years old, and beat them for it when they are ten, and separate them in their beds." Neglecting the education of children is a disservice to them and a primary cause of their corruption. The Prophet, peace and blessings be upon him, said: "No father has given his child a gift better than good manners."