Check SMART status in your OS (Windows: Device Manager → Disk drives → Properties → S.M.A.R.T.; macOS: Disk Utility → select drive → S.M.A.R.T. status if available; Linux: `smartctl -a /dev/sdX`)
Run SMART diagnostics using vendor tools (Samsung Magician, WD Dashboard, Seagate SeaTools, Crucial Storage Executive)
Use a third-party SMART tool (Windows/Linux: CrystalDiskInfo; Linux: `smartctl`)
Check for reallocated/pending sectors and unreadable errors (SMART attributes like Reallocated Sectors, Current Pending Sectors, Uncorrectable Errors)
Review drive health indicators like “Overall Assessment/Status” from SMART tools
Check drive temperature and thermal history (SMART attributes like Temperature; ensure it stays within manufacturer limits)
Verify power-on hours and usage patterns (SMART attributes like Power On Hours/Power Cycles)
Inspect error log entries (SMART Error Log / Self-test log)
Run a short/extended self-test (SMART self-test options in `smartctl` or vendor tools)
Check filesystem errors (Windows: `chkdsk`; Linux: `fsck` where applicable; macOS: Disk Utility First Aid)
Confirm the drive is reporting correctly in the OS (no disconnects/timeouts; stable capacity and device identity)
Monitor performance for signs of degradation (increasing latency, frequent stalls, abnormal read/write speeds)
Check interface/cable/port issues if errors are frequent (swap SATA/USB enclosure, cable, or port; reseat connections)
Back up immediately if SMART shows “Fail,” “Critical,” or multiple high-severity SMART errors
Replace the drive if SMART self-tests fail or uncorrectable/reallocated/pending sectors continue increasing