The Right Length for a PlayIn general, 90 minutes can please a lot of people. Technology has helped too. When I saw the Las Vegas 'Phantom,' which is about 90 minutes, I was amazed that it seemed to contain almost all the same material found in the three-hour 'Phantom of the Opera.' Even the director, Hal Prince, admitted to me that he didn't miss much that he'd cut, arguing that it was at least partly filler to cover scenic transitions that computers can now engineer more quickly
(from Chicago Tribune).