I've found that a lot of music takes 5+ listens before I really start to enjoy it. This is particularly the case of complex, subtle music. This could be just me adjusting to social demands but I find it can happen even with music I want to dislike. Katie Perry grows on you.

As people learn more about an art form, they can more-easily predict it, and need more and more novelty to keep them interested; like porn viewers who seek out movies with continually-stranger sex acts. (This is a cognitively-plausible variant of "there is no such thing as objective beauty".) If there were departments of pornography at ivy-league universities, they would scoff at the simplicity of films lacking bondage, machines, or animals.

Most of what I listen to is popular music and I find that a lot of the music I used to love just goes down too easily now. It's a very similar experience to eating sugary candy you loved as a child but is too saccharine now. When I listen to new music that is at similar levels of accessibility and ease of listening this manifests itself in a lower limit to the number of times I can hear the song without getting sick of it.