Usually used equipment is sold without guarantees after a random standard check or under the contract non-working equipment is exchanged for working one.
Anyone that does not offer DOA is clearly sending you units that are not functioning.
If you are offered DOA service by the seller when shipping from another city or country, you can be easily cheated.
In Russia, the equipment is usually checked by the buyer or a guarantor, and then the transaction is done.
I know many stories when miners bought cheap equipment in China without checking, and half or more of it was not working. But the price was very sweet.
And due to the very low price in 50% of cases the buyer was in profit and in 50% of cases in loss.
If a miner does not understand the golden rule of buying used equipment, he will pay with his wallet for his stupidity.
Translated with DeepL.com (free version)