Why hours and age don't tell you much
Onyimadu's 1TB Seagate has about 2.2 years of cumulative runtime, which works out to roughly six and a half hours per power-on session. By most rules of thumb that sounds like a drive on borrowed time. Those figures only describe how much the drive has been used. They say nothing about whether the platters and heads are producing sectors the drive can no longer trust.
Reallocation is a record of exactly that. When firmware gives up on a sector, it quietly redirects that address to a spare. Windows doesn't expose this, so File Explorer keeps opening your files normally while the counter climbs. Remapping also doesn't repair the original sector. The drive has just stopped using it.
These are one author's reported readings from one drive. They aren't a measured result for Seagate drives in general.
How to check it in Windows
- Download and install CrystalDiskInfo, then launch it.
- Look at the health badge at the top, but don't stop there.
- In the attribute table, find Reallocated Sectors Count (05).
- Read the Raw Values column. That is the actual count, shown in hexadecimal, so
000000000000is zero. - Check Current Pending Sector Count (C5) and Uncorrectable Sector Count (C6) as well.
The Current, Worst and Threshold columns are normalized scores set by the manufacturer. In the example drive, the attribute 05 row read 100, 100 and 36. These scores are harder to interpret across vendors, which is why the raw value matters more.
One repair-shop guide gives a clear contrast. A current value of 100 with a raw value of 0 is perfect, while a current value of 99 with a raw value of 48 means the drive has already remapped 48 sectors.
Hexadecimal trips people up. Raw values display in hex, so D0 is 208 and 0D is 13. A forum thread about a Toshiba backup drive shows how easily this goes wrong. The poster's drive showed D0, which a helper decoded as 208 bad sectors.
What triggers the yellow badge
CrystalDiskInfo's own documentation says its HDD "Caution" status appears when the raw value of attribute 05, C5 or C6 goes over a threshold set in its Health Status Setting. The badge is a useful summary, but it depends on that setting and on what the drive reports. It is not a universal verdict. One forum user noted that a drive reading "Healthy" had all-zero raw values, while a drive with any bad sectors would normally show Caution.
How to check it on Linux
The article uses smartmontools:
sudo smartctl -A /dev/sda
The -A option prints the drive's vendor-specific SMART attributes and values. /dev/sda is only an example path. Identify your own drive first, because the wrong device name will show you the wrong disk. If you want everything, -a (--all) prints all SMART information.
Whichever tool you use, write down the raw value and the date.
The trend matters more than the total
A single number is a snapshot. The useful signal is how it changes between checks:
| What you see across checks | What it suggests | Sensible response |
|---|---|---|
| Stays at 0 | No recorded reallocations | Keep using it and back up as usual |
| Small number, unchanged (8, 8, 8) | A past problem that hasn't worsened | Keep backups current and recheck periodically |
| Keeps climbing (8, 17, 42) | The drive keeps hitting sectors it can't trust | Back up now and plan a replacement |
CrystalDiskInfo's maintainer takes the same view in guidance on the Caution state. A small nonzero value doesn't necessarily mean imminent failure, but if it keeps increasing, the recording surface may be deteriorating.
What Backblaze's data adds
Backblaze's analysis of its data-center fleet is the best-known large-scale look at this. It watches five HDD attributes: SMART 5, 187, 188, 197 and 198. In its 2016 data, 76.7% of failed drives had at least one of those five above zero, against 4.2% of operational drives. That also means 23.3% of failed drives showed no warning from those stats.
Backblaze also says a small nonzero SMART 5 value, such as two remapped sectors, means little on its own. It becomes meaningful when combined with other factors, and Backblaze says time matters too because most of these counters are cumulative. Its worked example of a rapid jump involves attribute 187, not 05, so treat it as a principle, not an attribute-05 threshold. These are fleet statistics from enterprise-style deployments, not a failure probability for a laptop drive.
Pending sectors
The Current Pending Sector Count (C5, listed by Backblaze as SMART 197) covers sectors the drive had trouble reading and hasn't yet remapped. The value may fall if the sector is later read or written successfully, or it may become a reallocated sector. Backblaze notes that 197 is the exception to the cumulative pattern, so it can go down as well as up. Different tools use different ID notation, so don't assume every utility labels these rows identically.
SSDs are a different story
Don't apply the HDD logic to a solid-state drive. Onyimadu's WD SN530 NVMe SSD showed "Percentage Used" as 0D, which is 13 in hexadecimal. That reflects 13% of estimated endurance used. It is not a promise that 87% of the drive's life remains. CrystalDiskInfo's health-status documentation shows that SSD indicators vary by controller and vendor. Examples include Intel's reserved-space attribute, SandForce's "SSD Life Left" and Micron's "Percentage Of The Rated Lifetime Used". Read the endurance figure for your specific drive and don't hunt for attribute 05.
What the data can't tell you
- Zero isn't a guarantee. Drives can fail without warning, as Backblaze's 23.3% shows.
- Nonzero isn't a death sentence. Forum users report drives running for years with a stable count. That's anecdotal, but it matches the maintainer's guidance.
- Checking SMART doesn't scan the surface. One forum commenter points out that SMART may not update just because you look at it. A full read check is a different test.
- 20,000 hours is not a threshold. Nothing in the evidence supports a particular hour count as the point of failure.
What to do about it
- Keep regular backups regardless of what SMART says. Don't leave important data in one place.
- Record attributes 05, C5 and C6 with dates. Monthly is a reasonable rhythm for a drive you rely on. This cadence is my suggestion, not a figure from the sources.
- If CrystalDiskInfo shows Caution or Bad, its maintainer says to back up your important data to another storage device before investigating the cause.
- If the count rises between checks, treat the drive as short-term. Back up now and budget for a replacement.
The bottom line
Hours and power cycles describe a drive's history of use. The raw reallocated-sector count describes problems it has actually recorded, and whether that number is moving tells you far more than the drive's age does. Onyimadu's Seagate stays at zero, so it keeps its place in the laptop. If that raw value starts to climb, he plans to stop treating it as a long-term keeper, and that is a sound rule for anyone's spinning disk.