Danger of treating all pupils the same, and of applying received theories of technique unquestioningly. Unrealistic standards of perfection from listening to edited performances on CD. A fixed position of the wrist. Strongly curved hand position - particularly with clenched fingertips. Returning to a full practice regimen after a holiday or other break from the instrument. My personal view is that more than four antique piano hours a day is unnecessary for most people if efficient practising techniques are used. I have not dealt with all the other kinds of pianists, such as orchestral players, lieder, duo and chamber music specialists and repetiteurs. I feel that more time spent on this results in fewer injuries and better informed performances.