From a health point of view, how often is the best time to wash your hair?

It is best to wash it once a day. I always do, even in cold weather. Because people will get too much dust and oil stains on their hair during the day's activities, resulting in dry hair and easy splitting, it is necessary to wash your hair in time and shampoo is also very particular. Personally, I prefer to use Rejoice shampoo … and I have been using this … haha … to advertise Rejoice …