RE: At what yardage do you guys "lose it"?
Practicing at long ranges is a great aid to accuracy. You will be able to judge your consistency, arrow flight, etc. better. If you can group arrows at 50 yds, 20 yds is a piece of cake. It also helps you learn to focus better--just like grouping, if you can pick a tiny spot at 50 yds, it makes picking a spot at 20 a lot easier.
Chad