We just helped my daughter move to an apartment in Boston. She asked, "How did people sell their used furniture before Craigslist?"
My wife and I decided that part of the answer is that people moved more stuff back in the old days. The transactions cost in buying and selling used furniture have fallen relative to the cost of renting a truck to make an interstate move.
I am a huge fan of buying used household furniture, especially compared with new stuff you have to assemble. My daughter got a used book case for $20, and it was already put together. Because of that, I was thinking that the condition of the book case was "better than new."