It was repeatedly noticed that SMART attribute N195(Hardware ECC Recovered) on last Quantum models(including Quantum-Maxtor models) reflects the condition of heads. If its number rapidly began to fall(noticeably differs from 100), and raw number began to rose, the HDD's heads will be broken down in nearly time . Before failure happens, hard disk device could sometimes freeze and make a soft knocking sound.
If Selfscan test is launched - hdd with such problem will halt on N4-SvVfy or on offtrack read-write test.If mentioned in advance - it is possible to save all imortant data in a save place.
Thus sometimes SMART gave us a useful information. It didn't forecast anything useful for a long time so people stopped to believe it.

But in this case - attribute N195 could certainly tell us how long this device would live.