Speaking for myself only, I'm not going to make the same mistake that I made with my modest vinyl collection; that is, giving it away. I do cull the collection occasionally and get rid of CDs that I don't like anymore, or tried and never liked. I don't keep CDs just for the sake of having a larger number of them.
I continually add to the collection and don't plan to ever stop. I love the physical media, and educating myself about artists through the liner notes. Goodwill has been a great source of new music for me besides new online purchases. Just like when CDs became popular and many gave away their LPs for little or nothing, this is a great time for purchasing CDs.