Skill Drills are the way the Chinese Boxing Theory is built into the human body and mind.  Operating on the Theory which involves yielding to force and efficiency, the body needs to develop automatic responses to touch and, at times, sight.  In order to build in the correct body reaction and not the wrong one, drills are done giving one the ability to practice the right response in repetition to begin to execute the art.  Of course this is tested in the Dueling Board.  Even in the Skill Drill exercises shown one can increase the options to provide limited duels when one is ready.  In the development of these reactions it is recommended that one progress from slow gradually to fast.