Is it permissible for men to grow their hair long?

The Shaykh : And in these hadiths there is evidence that growing the hair is not a recommended practice (sunnah). The meaning of growing the hair is that a person leaves the hair on his head until it becomes abundant, thick, or long. It is one of the customs. If it had been a recommended practice (sunnah), the Prophet (peace and blessings be upon him) would have said, "Leave it; do not shave it," regarding the boy. And he did not shave the heads of the children of Ja'far ibn Abi Talib (may Allah be pleased with him). However, growing the hair is a custom: if people have adopted it, then adopt it; and if people have not adopted it, then do not adopt it. As for those among the scholars who hold that it is a recommended practice (sunnah), that is their independent legal reasoning (ijtihad). The correct view is that it is not a recommended practice (sunnah), and that we do not order people to grow their hair. Rather, we say: if people have adopted it and it has become the norm for people to grow their hair, then grow it so that you do not deviate from the custom. But if they do not grow it, as is known in our current era, then do not grow it. For this reason, our great scholars, such as Shaykh 'Abd al-Rahman ibn Sa'di, Shaykh Muhammad ibn Ibrahim, Shaykh 'Abd al-'Aziz ibn Baz, Shaykh ibn Humayd, and other scholars, do not grow their hair, because it is not a recommended practice (sunnah), but rather a custom. And success is from Allah.

The questioner : ...