For what it's worth, lyrically, I use a lot of repetition myself, but I do think it's more interesting if that repetition of lines sets up something poetically and storywise. I'm more likely to repeat the first part of a line and change the end of the line-
Oh when I got there I knew there'd been trouble Oh when I got there I knew what he'd done
Or you can use the break in pattern to say something...
Life life life life Strife strife strife strife Knife
I've also noticed that listening to foreign language music can be fun because you focus on the voice as a musical instrument instead of as something telling a story.
By repeating something in music, you are telling the audience that it is important. We don't have many ways to communicate the importance of an idea to audiences, but repetition is one of the ways to do so.
It also enables the audience to interact with the music. When you break away from some repetitive pattern, it builds interest. When you later return to the pattern, the listener will ask, "I wonder what he'll do this time." ---------- Marc Graci YouTube Channel
It's fundamental to how our brain (a pattern recognition engine) operates. Striking that balance between the familiar and the novel underlies almost everything we do. Where you place yourself on the continuum dictates to a large extent how receptive people will be to whatever it is your doing. Pop music obviously sits tightly at one end, though you also could argue they innovate through sound design and instrumentation rather than composing/arranging.
There's science to it but making it work well is art.