Most composers, most of the time. Beethoven, on the other hand, refused to rewrite portions of the Ninth that were maybe too high for some to sing, and you can probably find difficult instrument parts if you chat to, say, Bassoon players.
> As practice gradually moved away from this insular model, and standing, virtuoso quartets replaced ad hoc groups as the chief vehicles of chamber music performance, Beethoven’s compositions became increasingly experimental (and daunting). Legend has it that when Ignaz Schuppanzigh—a well-known Viennese violinist and Beethoven supporter—complained about a particularly difficult passage in one of the Op. 59 quartets, the master retorted, “Do you suppose I am thinking about your wretched fiddle when the spirit moves me?”
