You must diligently practice all scales.

I believe this matter of insisting upon a thorough technical knowledge, particularly scale playing, is a very vital one. The mere ability to play a few pieces does not constitute musical proficiency.

Scales should never be dry. If you are not interested in them, work with them until you do become interested in them.

Give special study to passing the thumb under the hand and passnig the hand over the thumb. This makes the practice of scales and arpeggios indispensable.

I consider the practice of scales important not only for teh fingers, but also for the discipline of the ear with regard to the feeling of tonality (key), understanding of intervals, and the comprehenson of the total compass of the piano.

Do you ask me how good a player you may become? Then tell me how much you practice the scales

I don't like to practice, never have. but when I do get started at the piano, for the first 10 minutes i play scales, slowly. I've done this all my life. listen to the sounds you make. The sound of each tone will generate a response in you. It will give you energy.