A card used for mining will have worn out fans and potentially damage from heat on it. You'll have to hope for really cheap used cards to make up for that.
I'm running my GPU in mid 50s Celcius, with plenty of case cooling. (Lowered the power target etc.)
I think goda90 was referring to the second hand market.You may have taken good care of yours, but I suspect that miners won't have been as careful so buying these could be a bit of a crapshoot
When it comes to GPU mining (especially ETH) it is very common to undervolt / power limit a GPU as it reduces power usage greatly so the temperatures are lower than usually. Power consumption together with the price of kWh is an important factor that affects mining profitability
Yes but they are still stuck in open air cases in not exactly pristine environments.
Getting a GPU that has been running 24/7 for 2-3 years will be the mother of all lotteries.