While analyzing the hard disk reliability, use the parameters that indicate the hard disk aging: an amount of power cycles, an amount of engine’s rotation during operation, an amount of head moving and other.
Modern hard disks are not also able to receive information about the state, for example about the speed of data exchange between the medium surface and disk cache-memory, the search speed and other, but it is able to restore bad sectors independently.
The usage of the hard disk testing (a value “Enabled”) causes the decreasing of a computer’s performance, so it is recommended to use S.M.A.R.T. technology if you use the outdated hard disks or the disks the data on which have sufficient value. In all other cases, this parameter can be switched off (a value “Disabled”) and it should be switched on only if there are some error messages affecting the work of the hard disk.