From the 2011 Nike Coach of the Year Clinic:
Each year we do a self-scout at the end of the year…. After the review, we could see where we made mistakes of adding plays that we did not have time to perfect. We have decided to stop running plays we add late in the week, and we do not have enough reps where our players feel comfortable running them. We may add a play to take advantage of a team that widens their 3-technique. We work on that all week, and when we get into the game, the opponent does not widen the 3-technique, and we have wasted a lot of time working on something we did not need.
I want to encourage you to stay away from doing that next season…. You will see something you think will work, and you think it will help you in the next game. You get to the game, and you see it does not work. You need to go back and call the plays the players know; just call them from a different formation.