Typically, the hair should be ¼ inch or 5mm long if you want to wax. It takes around 3 to 4 weeks to reach this stage but the hair re-growth pattern of each person varies. While few people notice a faster growth pattern, others have a slow hair re-growth pattern. Thus, the best way to determine this is to wait for the correct length. Don’t rush for the sessions because smaller hair strands don’t grip well with the wax and you might have to wax a particular area 2-3 times. This can be painful. Use correct products so that the skin stays smooth till then. If you want to do it at home, wax the hair in the correct direction to avoid irritation or bumps.