Does Erasing Flash Memory Shorten It’s Life?

Yes. Performing an erase or a "full format" shortens the life of the device. The erase function is also very slow. This matters more than most people realize because flash memory wear is cumulative and irreversible over time.

Here are some additional questions based on the answer above which we will address in today's post:

Is "erase" and "format" the same thing?

Erasing flash memory (a.k.a. setting all bits to 0, also called a "full format" by Windows) does more damage. Flash memory has a limited number of times that it can be written, and the more you write to it, the more it degrades. With an erase function, you're writing to the entire device.

With a format, all that's happening is changing a few bits at the front of the device to indicate the rest of the memory space on the flash drive is available to be overwritten. This preserves the life of the flash memory because the old data isn't being overwritten immediately—just flagged for reuse later. We've covered the broader implications of flash wear and longevity in more detail in our article on the life cycle of a USB flash drive.

Why would you need to erase a drive?

Since a format only changes a few bits at the front of the device, it means all the data is still physically on the drive. The bits being changed are related to the file allocation table. Once those entries are removed, there are no longer instructions pointing to where the files are located. Recovery software can scan the raw memory space and retrieve those files even though the file allocation table no longer provides directions.

Think of the file allocation table as the table of contents of a book. If you tear out the table of contents but leave all the pages intact, the story is still there—it's just harder to find specific chapters. Formatting a drive works the same way. Erasing, on the other hand, is like shredding every page so nothing meaningful can be recovered.

Coming back to the original question, why would someone want to erase a USB flash drive? A common reason is data security. If you are donating, selling, or repurposing a drive that once contained financial records, medical data, or confidential files, an erase operation ensures that data cannot be recovered using standard tools.

Why does an erase take longer?

This gets a bit more technical, so we'll keep it high level. NAND memory is made of silicon, and that silicon is organized into planes, blocks, and pages. A page is the smallest unit that can be programmed, but a block (which contains multiple pages) is the smallest unit that can be erased. When you perform an erase or full format, each block must be accessed and cleared page by page. That takes time.

When you format or delete a file, the binary data isn't immediately removed. Only the address pointing to that data is cleared. Using the book analogy again, tearing out individual pages one by one is much slower than removing a whole section at once—and that's why erase operations take significantly longer.

Why does an erase function shorten the life of the device?

Since a format function doesn't materially change the stored data, there's minimal wear. An erase function, however, forces electrical changes across every block of silicon. Flash memory stores data using electrical charges. Over time, repeated charge and discharge cycles prevent the silicon from reliably holding those charges. When that happens, blocks are marked as unusable and removed from service, reducing total capacity and lifespan.

As you can see, an erase function isn't required unless you have a specific reason to use it. Because it's slower and shortens the life of the device, it's best avoided unless data security or compliance demands it.

Source: GetUSB.info (English)
Reference: Flash Translation Layer (FTL) – Wikipedia