If I have an exact same copy of a game that isn't a variant, I generally will see if my local brick and mortar will give me store credit for it. Otherwise if there is a big enough gap, I will eBay it. I mean if there is a $10 difference between what the brick and mortar gives me and what I walk away with after eBay fees, PayPal, shipping, etc. I will go eBay route.

I dont f*** with Craigslist anymore because I got tired of endless correspondence with trying to figure out an agreed upon time to meet as well as the inevitable haggling. and of course it always feels like a drug deal to me to meet a stranger at a gas station and exchange money.

Ive never considered donating them because Goodwill has become a pawn shop essentially and Savers, well I know their employees essentially take the games home with them from what Ive heard

I generally dont hoard copies of a game and since I dont run a game store myself I dont see the point in keeping extra copies around. If a disc stops working I can just get it resurfaced