She said that you never repeat a command. You issue it and either punish or reward as fit. By repeating all you do is teach the dog that it can respond when it wants to, it made me think of those times I've seen parents yelling (or even just telling) at their kids over and over to behave. If instead they were consistent and said "stop" and punished the child if he didn't behave, then he'd learn pretty quickly that what mom and/or dad sais, goes, and right away.