Revising has long been a common practice among composers. J. S. Bach made changes as a matter of course when making a new copy of a work. Chopin revised habitually, even marking changes on published versions of his compositions.
Several composers whose music I love reworked some of their compositions over periods lasting years. Berlioz, for example, based his Damnation of Faust on a work he had composed 17 years earlier. Tchaikovsky completed the final version of Romeo and Juliet 20 years after the premiere of the first. Stravinsky made revisions for various reasons, including numerous changes and additions of detail in his orchestrations. Mahler revised most of his symphonies extensively.
Such decisions to revise usually stem from a persistent pursuit of eloquence.
After I began writing librettos and operas, I increasingly approached my work with a dramatist’s frame of mind (as discussed in On Theater.) And the more experience I gained working from within a theatrical perspective, the more I wished that I had composed and orchestrated some of my earlier works with more élan—with more vivid exteriorizing of fervor.
By the late 2000s I had gained enough experience working in the theater to be at ease making revisions to better shape dramatic flow and effect. After that, if I looked back at one of my earlier orchestral scores, then I sometimes found myself spontaneously revising passages in my head—hearing them performed differently in my mind than the way I had originally imagined them.
These differences were often subtle—changes of texture, orchestration, rhythmic detail, and so on—but when I imagined the cumulative effect of such changes, the differences in expressive effect were often remarkable. Realizing that, I sometimes took the time to revise the earlier score to match the music I was now hearing in my more unrestrained imagination.
In some cases small revisions triggered others, and a few changes cascaded into an extensive reworking of an entire score. If I eventually found myself approaching this reworking using a new poetic or theatrical concept, then the revisions have sometimes included substantial structural changes, and, in rare cases, a new title that better suggests the new concept.