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Quick answer: On Windows, open PowerShell and run Get-PhysicalDisk | Get-StorageReliabilityCounter, or install the free CrystalDiskInfo for a full SMART readout with a simple Good / Caution / Bad verdict. On macOS, open Disk Utility, select the drive and check the SMART status line. Wear below 90% used, zero media errors and a Good verdict mean the drive is fine.
Method 1 – CrystalDiskInfo (Windows, easiest)
Download CrystalDiskInfo (free, no adware in the standard edition), run it, and read the header: Health Status gives a plain verdict plus a percentage. The three values worth checking underneath:
- Percentage Used: flash wear consumed, lower is better.
- Reallocated / Bad Block Count: should be zero or a small stable number.
- Media and Data Integrity Errors (NVMe): should be zero, growth here is the real red flag.
Our pick for this guide: Samsung 990 PRO 2TB NVMe SSD
If the health check in this guide shows a falling percentage or reallocated blocks, the only real fix is replacing the drive before it fails rather than nursing it along.
Method 2 – Built-in Windows commands
No installs needed. In PowerShell run Get-PhysicalDisk to see the HealthStatus column, then Get-PhysicalDisk | Get-StorageReliabilityCounter | Select Wear, ReadErrorsTotal, Temperature for wear and error counters. The classic wmic diskdrive get status still works for a quick OK check on older systems.
Method 3 – macOS Disk Utility and smartctl
Open Disk Utility, click the physical drive (not the volume), and look for SMART status: Verified. For detail, install smartmontools via Homebrew and run smartctl -a disk0 to see percentage used, spare blocks and error logs.
Method 4 – The manufacturer dashboard
Samsung Magician, WD Dashboard, Crucial Storage Executive and similar tools show the same SMART data plus firmware updates, which occasionally fix real reliability bugs. Worth installing once for the firmware check even if you use CrystalDiskInfo daily.
Reading the signs of a dying drive
Replace the drive soon if you see: growing media error counts, files that suddenly become unreadable, the drive disappearing from the system intermittently, or free space shrinking as spare blocks are consumed. Any of those beats a scary-looking percentage. When it is time, our guides to the best NVMe SSDs and best portable SSDs cover tested replacements, and cloning is covered by tools like Macrium Reflect in under an hour.
Frequently asked questions
What percentage of SSD health is bad?
The “Percentage Used” or wear indicator counts from 0 up to 100 as the flash wears out. Under 50 is nothing to think about. Past 90, plan a replacement, and past 100 the drive is running on spare cells with no guarantees. Reallocated sector counts and media errors matter more than the raw percentage.
How long do SSDs actually last?
For typical desktop use, far longer than people expect: most consumer drives are rated for hundreds of terabytes written, which translates to 5 to 10 years of normal use. Drives usually become obsolete in capacity before they wear out. Sudden controller failures, not flash wear, cause most real-world SSD deaths, which is why backups matter regardless of health numbers.
Does defragmenting help an SSD?
No, never defragment an SSD. Fragmentation is a mechanical hard drive problem. Windows already knows the difference and runs TRIM on SSDs instead, which keeps write speeds healthy. Manual defrag just burns write cycles for zero benefit.
Two minutes with CrystalDiskInfo or one PowerShell command tells you everything: check the wear level twice a year, watch for errors, and keep a backup running regardless.
