Hey I already know how to stand on guard. Maybe you do. If so, practicing it with a renewed awareness from a slightly different perspective will do you no harm at all and may even improve your execution of it. No one's is. There's a subtle and important difference between performing perfectly and having a perfect technique.
Perfection is temporary.
It exists only in the moment, then it's gone. You must pursue it constantly. It is never yours to keep. Most any virtuoso or champion will tell you that. They are all still striving to improve.