This article is from the Piano Playing from Memory FAQ, by Isako Hoshino rmmpfaq@yahoo.com with numerous contributions by others.
For at least the last 100 years it has been a tradition for
professional pianists to perform solo works from memory. (There
have been some notable exceptions - the famous turn-of-the Century
French pianist Raoul Pugno, Dame Myra Hess, and Bela Bartok
performed with scores. Svyatoslav Richter has done the same "in
respect for the composer", as he put it in an interview.) Today,
playing from memory is one of the abilities a professional is
expected to have. However, the tradition is often abandoned in
concerts where new compositions or contemporary pieces which are
difficult to memorize are played.
In the past, piano teachers observed the tradition by requiring
memorization for student recitals regardless of whether or not the
students would become professionals. Nowadays, in deference to
individual variations in abilities and requirements, some teachers
make memorizing optional.
 
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