I recently discovered/noticed there is a "used to own" button when looking at albums on rate your music.
So, since my current collection of music is about 100 pieces big, and the stuff I sold in the past reaches closer to 2,000ish, I have been, for fun, putting together a "used to own" section on rym.
It is good and bad. First, it makes me bummed that I don't still have this large physical music collection. But the other half of it is, there are tons of CDs, tapes and vinyl that I could care less about having, and would probably re-sell them if I still had them.
So. But it does make me remember the satisfaction of finally getting the last album needed to complete this or that band's discography.