The most important is the ability to keep proper proportions in the day planner. Johannes Brahms used to say that we should spend as much time playing as reading.

Every pianist has his favorite piano, on which playing he can bring out the most beautiful sound for him. But the pianists are not in such as comfortable situation as violinists or guitarists who can perform on the same instrument they practice on a daily basis.

While studying at the Secondary School of Music, I often heard the phrase spoken by my Professor Irena Rolanowska:

"There is no day without Chopin Etude"