Talked with friends at the local computer show. This is where 'the man on the street' shops and communicates. No marketing agendas but the real truth. From what I gather most all purchases on ebay confirmed that reseller’s pass-off used (so called refurbished) GPU’s as new. Besides the passing-on of former ‘Miner Cards’ in many other unscrupulous ways. So the word was to never use ebay as once the seller has your money its goodbye and no looking back! My own opinion in this matter is that ebay is just one step above Craiglist and where most expect bargain basement prices but full well knowing that not all things are what they seem to be!
This is bunk. eBay is heavily weighted toward buyers these days. If you buy something, even if it states, "No returns," you can file a complaint with eBay if the item doesn't work or is not what you wanted. Not only that, but most people offer 30 day return policies (the default for eBay), so someone could buy a card, use it for 25 days, and then say they want a refund. Thankfully, most buyers aren't that bad, and frankly if you get a "refurbished" card that's sold as new, at a decent price, you should have already guessed that it wasn't brand new. Beyond that, if it's fully refurbished with replaced thermal pads on the GDDR6X memory (for higher end RTX 30-series cards like 3070 Ti and above), you'll probably end up enjoying the card more.
I've replaced the thermal pads on a few GPUs recently, as a test. It doesn't matter the brand or model, if you have a 3080 that was running the memory at 100C or higher, you can usually drop that to 80C with good thermal pads. And if your GPU is clean and running cool and performs as expected, it will probably continue to do so for some time. If it has issues right when you get it, you file a complaint with eBay and get a refund.