Successful music-making is like driving home from school.
The first time I drove home from school, I was on high-vigilance mode. I understood the route, but I didn’t know the route. By the fiftieth time, I probably drove home without actively seeing any of my surroundings.
To do that I needed keen situational awareness. To navigate safely without constant active awareness requires a deep knowledge of what you’re seeing so you don’t have to see it.
Think about how often you notice a new piece of art you hang on your wall, versus one that’s been hanging there for years.
In the same way, successful music-making requires the same deep knowledge of your surroundings. You need to know what every voice part is doing around you so well that you can take it in without spending brain space on it. That saves your active attention for reacting in the moment to make the music come alive.
It’s easier on a homophonic piece than with counterpoint, easier on a diatonic piece than a highly modulatory one. Essentially, the more you complex the music around you, the more time you need to have spent aware of it.
Deep situational awareness is a prerequisite for deep music-making. And the only way to get there is repetition.