I can't stand to sing the same song the same way two nights in succession, let alone two years or ten years. If you can, then it ain't music, it's close-order drill or exercise or yodeling or something, not music.
Source: Lady Sings the Blues, ch. 4, 1956.
-- Billie Holiday, (Apr 7 1915-1959), US singer; She was a noted jazz vocalist whose 1956 autobiography, Lady Sings the Blues, inspired the film, 1972.