If the directions say thati would check it at 4 or 5 days. It will take a few days to get to the right s.g. If you check at day 4 then again at day 5 you could get an idea of how many points its droping per day, roughly. But its best not to mess with it more than you have to. This is my opinion im sure others will chime in and let you know what they would do. There are as many ways to make wine as there are people who make it...