I've been wondering if I could benefit from having a recorder that has more than two channels. I've been shooting mainly zero budget films, and have been borrowing Zooms and cheap Edirol recorders. But I'm wondering when, if ever, I'd use more than two channels when doing a film. I, of course, use just one channel most of the time. On occasion, I've used two when we miked a scene with two separate mics on two separate booms. And I can see using a set up with a boom mic and a lavalier for an interview. But, when would I use more than two channels, since I can't imagine using more than two mics or line sources when filming.