Repetition in songs can be a really great thing, but if you repeat something one too many times, it becomes really boring really fast. The rule of twos basically states that if you do something twice, don't do it again until you've done something else first. Generally speaking, this principle applies throughout all music on both the micro and macro levels. In this "Rule of Twos" video, Steve not only talks about this basic principle, but he galsoives a lot of examples of what works and what doesn't.