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.
Yes indeed I have gained a lot out of playing scales and etudes.
Running through things because you are familiar with them, breeds routine and this is the seed of boredom.
Being unprepared heightens nerves.
Taking drugs to overcome nerves is the thin edge of the wedge going in there.
By the time I got to the Paris Conservatoire I was very good at the scales and arpeggios.