1.   Berton did compose, but preferred to be a musical updater of repertory works.

2.   But many operas with hapless librettos are timeless repertory works.

3.   Early in his career he performed standard repertory works, including the big Romantic concertos.

4.   Soloists usually play standard repertory works from memory.

5.   True, there are now a few centuries of important repertory works that musicians must maintain.