I dont have a store nearby, so i do most of my headphone exploring by buying and reselling used headphones. Havent made a profit nor a loss in 20 or so headphones. But in my country (Netherlands) the market is pretty bad, especially with the higher end stuff. People try to sell their (ab)used stuff often for more than new price and get annoyed when you offer them a more realistic price.
I live in Brazil, so used stuff usually is more expensive than a new similar in a USA. New stuff is 2 or 3 times more expensive than USA.
Chifi is a bit different. Used prices for a bit less than a new sometimes. Because until recently one could import from China with no taxes.
But two months ago government decide to enforce a law to tax all importations above 50 usd in 90% of price + shipment. Below 50 usd is, for now, only 20% in taxes, could increase to around 50% next year nwespaper have reported.
This will destroy the used market for sure.