Composer Nic Collins was here the other day. He had an interesting insight that had never occurred to me. He tells his students that between five and ten minutes is the most dangerous length for a piece of music. A piece under five minutes can bore no one. A piece 15 minutes or more seems profound simply by virtue of its length, and generally receives the benefit of the doubt. But in between, a piece flirts with a certain attention threshhold, and can easily seem too long, or not serious enough in content to have gone past that five-minute mark.