Read on 2026-10-16. The endurance figures below are the examples the source gives. Your drive's own spec sheet has its own numbers.
Why flash wears
Backblaze, in its post “SSD 101: How Reliable are SSDs?” (April 5, 2024), says that almost all types of today's SSDs use NAND flash memory. It adds that when writing and erasing a NAND cell, electrons are sent through an insulator and back, and the insulator starts to wear. It also says that flash type memory cells can only be reliably programmed and erased a given number of times, which is measured in programmed/erase cycles, more commonly known as P/E cycles. The same post says that the endurance of an SSD, measured in P/E cycles, varies depending on the technology, but typically falls somewhere between 500 and 100,000 P/E cycles.
Bits per cell
The same post says that generally, as the number of bits stored per cell increases, the cost per bit decreases, but endurance and performance may decrease as well.
| Cell type | Bits per cell |
|---|---|
| SLC | One |
| MLC | Two |
| TLC | Three |
| QLC | Four |
The same post adds that with QLC, the drive can wear out sooner, especially as it fills up.
TBW, MTBF and the warranty
The same post says that terabytes written (TBW) is the total amount of data that can be written to an SSD before it is likely to fail. It adds that for the Samsung V-NAND SSD 870 EVO, all of the models are warrantied for five years or TBW, whichever comes first.
The post lists the TBW warranty of that line by capacity.
| Capacity | TBW warranty |
|---|---|
| 250GB | 150 TBW |
| 500GB | 300 TBW |
| 1TB | 600 TBW |
| 2TB | 1,200 TBW |
| 4TB | 2,400 TBW |
The same post says that mean time between failures (MTBF) is a metric used to gauge the reliability of a hardware component throughout its anticipated lifespan, and manufacturers provide these specifications for their products. It adds that MTBF specifications don't guarantee that your particular SSD will last for that specific duration; rather, they indicate that, based on a sample set of the SSD model, errors are anticipated to occur at a certain rate. It also says that a 1.2 million hour MTBF means that, assuming the drive is used at an average of eight hours a day, a sample size of 1,000 SSDs would be expected to have one failure every 150 days. The same post says that SSD manufacturers are increasingly marketing SSDs for specific workloads such as write-intensive, read-intensive, or mixed-use.
How long to expect
The same post says that an SSD should ideally last as long as its manufacturer expects it to last (generally five years), provided that the use of the drive is not excessive for the technology it employs. It adds that in its comparison of SSD and HDD boot drives, the failure curves were similar in the first three years or so and separated after four years, with the HDDs failing at a higher rate. It also says that so far the SSDs have maintained a 1% or less Annualized Failure Rate (AFR) through the first four years. The same post says that the one use case for which it has rigorous reliability data is as boot drives in its storage servers.
Backblaze, in its NVMe and M.2 post, says that SSDs have a more limited write cycle than HDDs, and while you usually don't run into this limitation as a typical computer user, if you're constantly saving large files like you would if you're working with media files, it's something to consider. It adds that it can be harder to tell when an SSD is failing, which means you'll want to make sure you're effectively monitoring your drives and backing up.
Signs of trouble
The same post says that an SSD has no moving parts, so you won't get an audible warning that an SSD is about to fail, but there are usually other signs of when that's going to happen. It adds that there is little consistency between the different SSD manufacturers in what SMART attributes they monitor and how they calculate drive life expectancy, so it is important to read the manual for your particular SSD.
The post lists these indicators that an SSD is nearing its end of life.
- Errors involving bad blocks.
- Files that cannot be read or written.
- A file system that needs repair.
- Crashing during boot.
- The drive becomes read-only.
Write budget from a TBW number
Years to reach the TBW figure
Type the TBW from the spec sheet and how much you write to the drive each day.
- Years until the TBW figure is reached
Arithmetic only: TBW x 1000 / GB per day / 365. It is not a forecast of when a drive fails, and the warranty ends at the earlier of its years or its TBW. Nothing you type leaves your browser.
Sources
Checked on 2026-10-16 against Backblaze: SSD 101, How Reliable are SSDs?, Backblaze: SSD vs. NVMe vs. M.2 Drives. Read the source again before you rely on a number, because posts get updated and drive models change.
Related guides
- SSD vs HDD for home storage: How the two drive types differ, from the source's own comparison.
- NVMe vs SATA SSD: Interface limits, M.2 and what to check before you buy, with a transfer-time calculator.
- How long do hard drives last: Failure-rate data from a large drive fleet, and an expected-failures calculator.