Quote from: MINER_STONE on Today at 05:30:51 AM

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This kind of risk exists. What about buying second-hand miner machines?

The obvious question: why is someone selling their miners?

People like to overclock them with illegal firmware and then sell them off before the machines die.
Others put firmware in the miners so you are losing some of your mining.
Some well known sites that sell miners will also do this.
If there's some problem with the miner that doesn't happen all the time, people will sell these miners and claim they are ok.
Of course there's a truck load of 2nd hand miners being sold at ridiculously high prices also.

To be blunt, the 2nd hand miner market is higher risk.