How to identify a quality refurbished drive by its SMART values
Buying a refurbished hard drive and want to be sure it will serve you reliably? The key to a successful purchase is knowing how to read SMART values – diagnostic data that reveals the true condition of a drive. In this article we'll teach you which parameters to focus on and how to spot potential problems before you buy.
What is SMART and why does it matter
SMART (Self-Monitoring, Analysis and Reporting Technology) is a diagnostic system built directly into every modern hard drive. It continuously monitors dozens of parameters and records statistics about the health and performance of the drive. Thanks to this data you can estimate how long the drive will last and whether an early failure is likely.
To check SMART values you can use free programs such as CrystalDiskInfo, HD Tune, or Hard Disk Sentinel. These tools display a clear table of all measured parameters including their current status.
Key SMART values for HDD drives
For classic mechanical drives (HDD) focus primarily on these parameters:
Power-On Hours (POH) – Operating time
This figure shows how many hours the drive has been in operation. For refurbished server drives it is not unusual to see 20,000–40,000 hours. Quality server drives are built for a lifespan of 50,000+ hours, so even a drive with high mileage may have years of reliable service ahead of it. More important than the raw hour count is the combination with other parameters.
Reallocated Sector Count – Remapped sectors
This is one of the most important indicators. When a drive finds a bad sector it automatically replaces it with a spare. A low single-digit count of remapped sectors is normal for an older drive. However, if the value grows quickly or exceeds dozens, that is a warning sign.
Current Pending Sector Count
Indicates sectors waiting to be remapped. On a healthy drive this value should be zero or very low. A higher number signals active problems with the platter surface.
Spin Retry Count
The number of attempts to spin up the platters. An elevated value may indicate problems with the motor or bearings – the mechanical parts that most commonly fail on HDDs.
Seek Error Rate
Errors during read-head positioning. Some manufacturers (especially Seagate) use a specific interpretation for these values, so it is important to know the context.
What to focus on with SSD drives
Solid-state drives have a different set of critical parameters:
Total Bytes Written (TBW) – Total volume of written data
SSD drives have a limited lifespan for their memory cells. Manufacturers specify a guaranteed volume of written data (e.g. 150 TBW). Compare the current value with the rated lifespan – a quality refurbished SSD should have used no more than 20–30 % of this capacity.
Wear Leveling Count – Cell wear
This parameter directly shows the degree of flash memory wear. The value starts at 100 % and gradually decreases. A drive with a value above 80 % still has plenty of life left.
Reallocated NAND Block Count
Similar to HDD, this shows the number of replaced bad blocks. Low values are acceptable; rapid growth is not.
How to evaluate SMART data when buying
When choosing a refurbished drive, proceed systematically:
- Check the overall health status – most diagnostic programs display a summary rating (Good/Caution/Bad)
- Compare critical values – remapped sectors, pending sectors, and for SSDs, cell wear
- Verify consistency – sudden jumps in values are worse than stably slightly elevated parameters
- Consider the drive's origin – server drives with higher hour counts are often more reliable than cheap desktop variants
Red flags – when not to buy a drive
Some situations clearly signal a problem:
- The remapped sector count is growing rapidly
- Current Pending Sector Count is higher than single digits
- The program reports a status of "Caution" or "Bad"
- For SSDs, cell wear is below 50 %
- SMART values are missing or have been reset (may indicate tampering)
Reliable purchase without worry
Analysing SMART values requires a certain level of knowledge and experience. If you don't want to spend time studying diagnostic data, choose sellers who carry out thorough testing on your behalf.
At importpc.cz you will find quality refurbished HDD and SSD drives that have undergone comprehensive diagnostics including a check of SMART parameters. We provide a warranty with every drive, so you have the assurance of a reliable purchase without risk.