Last year I've listened to more than 6k different songs. If you'd be generous for the math and say 12 songs an album, 9 euro per album it's still over 5k a year. Spotify is just cheaper for me, even the high seas would cost me too much in terms of time
I spent >100$ on concert tickets to listen to artists I found on Spotify. Probably would not have spent this money nor discovered those artists by listening to 50 songs downloaded 10 years ago from Limewire.
I listened to 6k songs, just because spotify has them.
Do i need it? Absolutely not.
I cancelled when they increased the price and i went back to buying an album for life from the discount bin and putting it on repeat with the other 20 albums i still owned.
Back when I had an ipod I spent days downloading songs. I don't think my listening habits changed all that much, now I just don't download them via "legitimate" routes anymore
I find it most useful as a radio replacement for this reason, you can't find a service with more quantity. Personal music collection is still my main source though.