I Think It Is Most Important For

Running Through Things Because You Are Familiar With Them, Breeds Routine And This Is The Seed Of Boredom.

You Can Sightread Better If You Know Your Scales And Arpeggios.

Being Unprepared Heightens Nerves.

Never Just Run Through A Study Because You Happen To Be Familiar With It, But Use It To See What You Can Get From It On This New Day Which Has Been Granted You.

I Think It Is Most Important For A Teacher To Play The Pieces And Studies That Are Being Played By The Student.