What is the ruling on paying a monthly sum to a hair care salon? Is this considered beautification for the husband if the woman is about to get married? And is it not considered extravagance if the husband is wealthy, and what are the conditions of his wealth in this case?

Hair care is required for a married woman, and it is considered a praiseworthy adornment for her husband, provided it is done in a way permissible by Allah and without extravagance. Extravagance varies depending on the financial status of individuals, whether rich or poor. If the expenditure on hair care is within reasonable limits, appropriate to the person's situation, and does not deplete their wealth or disrupt their priorities, then it is permissible.