Solid state drives fail differently from spinning disks, so the values that matter when grading them are different too. Age and hours say little. Consumed write endurance says a great deal.
Wear indicator
SSDs track how much of their rated write endurance has been used. This is the closest thing to a fuel gauge a drive offers: it reflects work performed rather than time passed, which is why two drives with identical hours can be in entirely different condition.
Total bytes written
The cumulative volume of data written over the drive's life. It is the most direct usage measure available and, read alongside the wear indicator, shows whether a drive served a light desktop role or a write-heavy one.
Remaining health
The check also reports a health_remaining figure, a
0-100 summary intended for quick triage across a batch. Treat it as a
first-pass sort, then read the underlying wear and bytes-written values before
making a grading decision on any individual drive.
Why hours mislead on SSDs
A drive left powered on for years in a lightly used machine may have consumed very little endurance. One with a fraction of those hours in a logging or database role may be close to its limit. Grading SSDs by hours reliably misprices both.
Reading wear across a batch
- Boot the ITAD Tools iPXE toolkit.
- Select Drive Health Check.
- Record the wear indicator, total bytes written and remaining health against the drive serial.
Results submitted with an organisation key are retained per serial, so wear can be compared across a batch rather than assessed one drive at a time.
Run the free bootable Drive Health Check
The ITAD Tools iPXE toolkit reads SMART data read-only, with no installed operating system and nothing to install on the machine.
Frequently asked questions
What does SSD wear level mean?
It reflects how much of the drive's rated write endurance has been consumed. Unlike hours, it tracks the work done rather than the time elapsed.
What is total bytes written?
A cumulative count of data written to the drive over its life. It is the most direct measure of how hard an SSD has been used.
Are power-on hours useful for SSDs?
Less than for spinning disks. An SSD powered on for years but barely written to can have far more life left than a heavily written one with fewer hours.
Does a high wear figure mean the drive is unusable?
Not necessarily. It indicates consumed endurance, which informs what workload the drive is still suited to and how it should be graded.
How do I read SSD wear without installing software?
Boot the ITAD Tools iPXE toolkit and run the Drive Health Check. It reads the values read-only, with nothing installed.