That all three drives lasted this long then failed within a month is very suspect. This sounds less like random failure indicative of the quality of refurbished

That all three drives lasted this long then failed within a month is very suspect. This sounds less like random failure indicative of the quality of refurbished drives in general, and more like a defect common to all three drives. Because of such plagues, data-centre operators often mix drives of different manufacturers, models, batches and ages. Running heterogeneous devices in a redundant array helps makes the failure distribution more random so that the safety margin is less likely to be suddenly overwhelmed by correlated failures.