Richard Osborne said this quote

In 1829 Rossini was at an age which has often proven critical in the lives of musicians, painters and writers. Lapses into silence far more complete than Rossini's, creative failures, suicides, and unanticipated deaths have been common in the middle to late 30s. As Charles Rosen has noted, 'It is the age when the most fluent composer begins to lose the ease of inspiration he once possessed, when even Mozart had to make sketches and to revise'.