Storage is cheap, and music (even in FLAC format) is small. You can fit tens of thousands of songs into a terabyte.
I download anything and everything. An artist I enjoy? Entire discography. I've only heard one song? Entire discography--there may be more I might enjoy! An artist in a genre I like but I've never heard? Entire discography.
I'm at over 125k songs, and I still feel like my collection is a sliver. I eventually want to reach 1m songs and truly become my own Spotify. Finding songs I've never heard before and that I end up loving in my own collection is a joy I can't describe.