How about SSDs and their lifespan? How many times can you overwrite a modern SSD until its lifespan ends?

The lifespan of a solid-state drive (SSD) is determined by the number of write cycles that the drive's flash memory can endure before it becomes unreliable. The number of write cycles varies depending on the type of flash memory used in the drive, but on average, most modern SSDs are rated for between 3,000 to 100,000 write cycles.

However, this number can vary significantly depending on the quality of the flash memory and the controller used in the drive, as well as how the drive is used and configured. Some SSDs can endure more than 200,000 write cycles, while others may fail after only a few thousand cycles.

To prolong the lifespan of an SSD, manufacturers use wear-leveling algorithms that distribute data evenly over all cells by the controller. This helps to ensure that all cells experience the same amount of wear over time. It's also possible to check the current status of an SSD using the SMART analysis tool, which shows the remaining lifespan of an SSD.

Another essential aspect to consider is the "terabytes written" (TBW) value, which estimates how much data can be written on the SSD over its lifetime. A typical TBW for a 250 GB SSD is between 60 and 150 terabytes written. This means a user would have to write 190 GB daily over one year to reach the TBW limit.

In conclusion, SSDs offer several benefits over HDDs, such as faster speeds, lower power consumption, and increased durability. However, their lifespan is limited by the number of write cycles the drive's flash memory can endure before it becomes unreliable. To prolong the lifespan of an SSD, it's important to use wear-leveling algorithms and to check the current status of an SSD using the SMART analysis tool. It's also important to consider the TBW value when choosing an SSD.


*** Update (on TBW Calculation and Write Amplification); March 28, 2025 ***:
Some readers have pointed out that it may seem contradictory at first glance for a 250 GB SSD to have “only” 125 TBW, even though, according to the datasheet, the flash cells can withstand 3,000 or more write cycles.

This apparent contradiction arises because the TBW (Terabytes Written) value is not simply “[capacity] × [number of P/E cycles].” Manufacturers account for the so-called Write Amplification Factor (WAF) in their TBW specifications, which stems from processes like wear leveling and garbage collection. As a result, more write operations occur internally than the actual user data being written. Additionally, a certain amount of over-provisioning is often factored in.

Therefore, while an SSD’s flash cells may theoretically handle thousands of write cycles according to the datasheet, the TBW rating may appear lower to the end user. In reality, the TBW figure is more of a guarantee value rather than a direct indicator of how many times you can rewrite “full capacity × number of cycles.”

In practice, many SSDs often last well beyond their stated TBW specifications. However, if you want to be on the safe side, aim for a higher TBW rating and avoid unnecessary write loads. Still, if you only occasionally use a secure erasure method (such as the 4-round Protectstar ASDA method with iShredder), the impact on the SSD’s lifespan is typically minimal—provided it is not run continuously.

More information:
iShredder: https://www.protectstar.com/en/products/ishredder
Protectstar ASDA algorithm: https://www.protectstar.com/en/secure-erase
Blog article: https://www.protectstar.com/en/blog/how-long-your-ssd-really-lasts-everything-about-write-cycles