Watch the Repetition in Chord Progressions online guitar lesson by Matthieu Brandt from Songwriting on Guitar
Any good song will have a balance between sections you repeat and creative elements that are new to the ear. Too much repetition will make a song boring, too many changes will make the listener grab for something to hold on to. To create space for a listener to zoom in on a certain aspect of the song, you need to limit the amount of changes in the other elements. Predictabillity by means of repetition is a fundamental tool for any songwriter worth his weight. Breaking an expected chord pattern is equally as important: keep the listener on his toes.
The use of repetition can differ between the individual song sections.