I've got over 53,000 songs from over 5,000 albums by roughly 2,400 artists on my server.
First, I've been collecting music for 45 years. I'm not in the habit of tossing out an old album just because I bought a new one. Second, my musical taste is very eclectic and not geared to what's currently popular or only the music of my youth.
Some days I have an urge for classical. That could be J.S. Bach, or Christian Bach, or it could be Offenbach. This past weekend I listened to The Subdudes and a few days before that I was on a "new flamenco" kick. The weekend before was an early 20th century jazz fest with Scott Joplin, Eubie Blake and others.
So, the point is, if I hear music I like, I buy it. Once I buy it, I keep it so I can listen again, whenever that may be. Do that for a couple of decades and one day you'll wake up and realize you have a bunch of music!