My wife and I just had a discussion similar to this thread. It was "why do singers need a video monitor"? My take was this: people who play instruments (a learned skill) usually don't need help remembering the song. Yet we can all sing (not necessarily great), but we can all do it. So why do singers forget the words? We all talk, we all sing. I remember words to songs I haven't heard in 30 years. The players don't forget. You don't see guitarists stop mid riff because they forgot. Yet singers can't remember the same thing they have been spouting for years. Why? Learn the damn song people. How can you call yourself a musician and not remember the thing that makes you what you are?