SSD Lifespan and TBW Explained: How Long Does an SSD Last?
TBW (terabytes written) is on every SSD spec sheet but most buyers don't know what it means. Here's how to read it and whether you'll ever reach the limit.
TBW: the only endurance number that matters
TBW (terabytes written) is the total amount of data a manufacturer guarantees you can write to an SSD over its lifetime. A Samsung 990 Pro 1TB has a 600 TBW rating — meaning Samsung warrants the drive will function correctly after you've written 600TB of data to it.
To put that in context: a heavy desktop user writes roughly 20–40GB/day to their primary SSD. At 30GB/day, reaching 600 TBW would take over 54 years. Typical gaming and productivity use never reaches the TBW limit before the drive becomes obsolete for other reasons.
TBW ratings by SSD category
| SSD | Capacity | TBW | Years at 30GB/day |
|---|---|---|---|
| Budget SATA (Kingston A400) | 1TB | 300 TBW | 27 years |
| Mid-range NVMe (WD Black SN850X) | 1TB | 600 TBW | 54 years |
| Performance NVMe (Samsung 990 Pro) | 1TB | 600 TBW | 54 years |
| Prosumer NVMe (Seagate FireCuda 530) | 1TB | 1275 TBW | 116 years |
| Enterprise SSD | 1TB | 5000+ TBW | 400+ years |
What actually kills SSDs in practice
Most consumer SSDs die from causes other than NAND wear: controller failure (electronics fault), power failure during a write operation causing corruption, heat damage from sustained overtemperature operation, or simply physical damage. Backblaze's hard drive statistics — the largest public dataset of drive failure rates — show SSD annual failure rates of 0.5–1.5% regardless of TBW consumed, comparable to enterprise HDDs.
The practical implication: backup your data regardless of TBW headroom. A drive at 5% of its TBW can fail from a power event just as easily as one at 95%.
SLC cache and write amplification
Consumer SSDs use a portion of their NAND as an SLC cache — temporarily writing data as single-level cell NAND (1 bit per cell) for speed, then rewriting it as TLC (3 bits per cell) in the background. Write amplification means the drive physically writes more data than you send it — a ratio of 1.5–3× is typical. A drive rated at 600 TBW may physically write 1000–1800TB of NAND program/erase cycles to service 600TB of host writes.
How to monitor your SSD's health
CrystalDiskInfo (Windows, free) reads S.M.A.R.T. data from your drive including total bytes written, percentage of life used, and reallocated sector counts. The Samsung 990 Pro and WD Black SN850X both expose detailed health data through their respective monitoring software (Samsung Magician, WD Dashboard). Check these annually to catch early warning signs.
Compare NVMe SSDs →
NVMe drives ranked by speed, endurance, and value — with TBW ratings for every model.