I've learned over time that music I actually like I like forever. Music I'm infatuated with I eventually forget about and don't go back to listen after a while. I've been listening to Led Zeppelin, Pink Floyd and a few others since middle school. Over time bands have been added to that list and always enjoy listening to. For example The Clash, Sex Pistols, Bright Eyes, Nas, Biggie, etc.
There is a lot of music I like for a while and is exciting, but doesn't make it onto my forever list. Others get added to that last.
Everyone is different though, enjoy music the way you enjoy. Live your own life.