How to check a used drive's health
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Before trusting any used or refurbished drive, read its SMART data. For hard drives, watch reallocated and pending sectors and power-on hours; on Seagate drives also read the FARM log. For SSDs, read the percentage of rated endurance used and total bytes written. Be cautious of HDDs past about 20,000-25,000 hours and SSDs near their rated TBW.
How to check a used drive (step by step)
Do this as soon as the drive arrives, before storing important data on it:
- Install a SMART tool: smartctl (smartmontools) on any OS, or CrystalDiskInfo on Windows.
- Connect the drive and read its full SMART attribute list.
- For hard drives, check reallocated sectors, pending sectors and power-on hours.
- For Seagate drives, read the FARM log (smartctl -l farm) for deeper field reliability data.
- For SSDs, check the percentage of rated endurance used and total bytes written (TBW).
- Run a long self-test (smartctl -t long) and a full read scan to surface weak sectors.
- If any figure is in the concerning range below, return the drive while you still can.
What the numbers mean
| Metric | Healthy | Concerning |
|---|---|---|
| Reallocated sectors (HDD) | 0 | Any non-zero and rising |
| Pending sectors (HDD) | 0 | Any non-zero |
| Power-on hours (HDD) | Under ~20,000 | Over ~25,000 (factor in price) |
| Percentage used (SSD) | Under ~10% | Over ~80% |
| TBW written (SSD) | Well under rating | Near or over rated TBW |
| Seagate FARM head health | All heads healthy | Any flagged head or high reallocations |
Hours are not everything
Enterprise drives are rated for far longer service than consumer drives, so a high hour count on an Exos or Ultrastar is less alarming than the same figure on a desktop drive. Read the hours alongside the sector and endurance data, and weigh them against the price.
The live table below ranks tested refurbished and renewed drives on Amazon.com by price per terabyte, so you can shop the value tiers with these checks in hand.
Buying storage in the US
Prices on this page reflect Amazon.com in US dollars. The deepest storage discounts land around Black Friday and Cyber Monday in late November, with Prime Day in July a strong second; outside those windows, day-to-day prices move little during the 2026 shortage.
Returns and warranty are simplest when the listing is sold by Amazon.com or an authorised US seller. For a single critical drive, prefer that over a third-party reseller so the manufacturer warranty applies cleanly.
Live prices right now
See all recertified and renewed drives ->
Frequently asked questions
How do I check a used hard drive's hours?
Read the SMART power-on hours attribute with smartctl or CrystalDiskInfo. As guidance, be cautious past roughly 20,000 to 25,000 hours, though enterprise drives are rated for far longer service.
What is Seagate FARM?
FARM (Field Accessible Reliability Metrics) is a detailed log on Seagate drives with deeper health and usage data than standard SMART, including per-head health. Read it with smartctl -l farm.
How do I know if a used SSD is worn out?
Check the percentage of rated endurance used and total bytes written in SMART. A drive near or past its rated TBW is near end of life; under about 10 percent used is healthy.
What SMART attributes matter most?
For hard drives, reallocated sectors, pending sectors and power-on hours. For SSDs, percentage used and total bytes written. Any non-zero and rising reallocated or pending sector count is a red flag.
Should I run a full test on a used drive?
Yes. Run a long SMART self-test and a full read scan as soon as it arrives, so you can return a weak drive within the return window before trusting it with data.
Are high power-on hours always bad?
Not necessarily. Enterprise drives are built for continuous duty, so high hours matter less than sector and endurance health. Read hours together with the other figures and the price.
Last updated: 2026-06-26 18:01:42 UTC. As an Amazon Associate we earn from qualifying purchases. Product prices and availability are accurate as of the date indicated on Amazon.com and are subject to change. Any price displayed at the time of purchase will apply. CERTAIN CONTENT THAT APPEARS ON THIS SITE COMES FROM AMAZON SERVICES LLC. THIS CONTENT IS PROVIDED AS IS AND IS SUBJECT TO CHANGE OR REMOVAL AT ANY TIME.