The development of pianoforte technique since Beethoven has been in some ways even more revolutionizing than that of the brass instruments; and pianoforte instrumentation, both in solo and in chamber-music, is a study for a lifetime.
Beethoven almost always has 2 flutes, and invariably 2 clarinets.
He often thought, If Beethoven or Chopin had centuries to compose music, imagine the treasures we would have.
Beethoven was trained in the greatest and most advanced musical tradition of his time.
Magnificent examples are Mozart's trio for pianoforte, clarinet and viola, his quintet for pianoforte, oboe, clarinet, horn and bassoon (imitated by Beethoven), his quintet for clarinet and strings, Brahms's clarinet-quintet for the same combination, and his trio for pianoforte, violin and horn.