barbirolli's repertoire was not as wide as that of many of his colleagues because he insisted on exhaustive preparation for any work he conducted. his colleague sir adrian boult liked and admired barbirolli but teased him for his meticulousness: "we can't all be like you and spend months studying these things and then have days of rehearsals before we conduct them. for some of us they're only sporting events." barbirolli was shocked by such levity. his approach was illustrated by the care he took with mahler's symphonies. his biographer michael kennedy commented, "it is ironical that the effort of composing the symphonies shortened mahler's life; interpreting them certainly put an enormous strain on barbirolli in his last decade." he found that mastering a mahler symphony took between 18 months and two years, and he would spend hours meticulously bowing all the string parts in preparation for his performances. his first performance of mahler's ninth took nearly 50 hours of rehearsal.