Why is repetition important in music?

Let’s do a thought experiment to answer this question. Close your eyes and try to imagine what non-repetitive music would sound like. That is music with absolutely no repetition of notes or rhythms. Is it melodically and harmonically consonant? Are the rhythms disjunct? Can you imagine a simple tune without repetition?

Here’s an original melody with no repeating notes or rhythms:

This is certainly not a bad melody, but if we look at the intervals between the notes we see repetition. There’s a descending major second between the G-F, E-D, and B-A.

Let’s try a melody with no repeating notes, rhythms, or intervals:

This is great! There’s no repetition anywhere, but now what happens next? If we move the melody to a different octave or other transposition we’ll have different notes, but the same rhythm and most likely the same intervals (unless you transpose diatonically). Logically, the length of a non-repetitive piece is dependent on the range of the instrument or ensemble.

This is all a very long way of saying one of the few maxims in music: repetition is essential.