Your goal is to release each shot under the same condition. I regained my sanity and quit BR competition long ago, but the only way I found to attempt that goal, is by using multiple wind flags. Many are made with an attachment that helps gauge the wind speed. So, you can watch them all closely, trying to find that common condition for each shot before time runs out. Or, identify the most prevalent condition, then shoot like hell when it shows up and get your group on paper. If you're a score shooter, that doesn't work well, since you care where each shot hits, so you have to try for a known condition in which you can place a shot. To answer your question, you need to check it as often as you can.