I still have the first album I purchased in 1972 "Black Sabbath Masters of Reality". I have since expanded my collection to over 3000 albums. It was a slow process. My method has varied over time. First, I like to buy Collections from people. I then go through them and cull out the albums that I already have or don't care for. But i do listen to them. This enables me to find new music from days gone by (and potentially go down a rabbit hole learning about the band or artist). I also buy individual albums to fill out the collection of an artist, something that I heard, or if just looks interesting.
Once a year, I listen to at least one side of each album I own to see if I am still interested. I often initially keep records for "historical" purposes, meaning the artist was important in their time. By going through each album, I get the make an updated decision. I can keep it or move it on. In the process I usually get rid of 100-150 albums to make room for incoming music.
3000 seems to be my sweet spot. Why so many? Sometimes I'm feeling like Zydeco, other times Hawaiian, Jazz, Blues, or Punk. I like it all. I love having guests over and have them call out what they want to hear, and I actually have it.
I don't stream music except in the car. This helps me find new music. I also have a few hundred CDs for when the music I desire is not available on vinyl.
No justification here, just my method, which is also making sure that they are alphabetized and clean. BTW I don't own a TV, so music is always playing.