Guide
How long an SD card lasts before failing.
There's no fixed expiration date, but there is a measurable wear mechanism: every flash memory cell supports a limited number of write cycles before it stops being reliable.
The wear mechanism, explained simply
SD cards store data in NAND flash memory cells. Every time you write or erase data on a cell, that cell suffers a cumulative microscopic wear, until after a certain number of cycles it stops reliably retaining information. This cycle count varies by memory type: SLC cells (one bit per cell) support up to 100,000 cycles, MLC (two bits per cell) between 3,000 and 30,000, and TLC (three bits per cell, the most common in current consumer cards) between 300 and 1,500 cycles.
Why "10,000 cycles" doesn't mean "10,000 uses"
Something that confuses many people: even though an individual cell may support on the order of 10,000 write-erase cycles, that doesn't mean the whole card fails after 10,000 photos. Modern cards use an algorithm called "wear leveling" that spreads writes evenly across all available cells, instead of reusing the same cells over and over. In practice, this means a normally used home card can last 10 to 12 years, even more than 30 in light-use scenarios.
The use that actually wears a card out fast
Usage pattern matters far more than capacity or brand. A dashcam or a security camera that records in a constant loop writes and overwrites the card hundreds or thousands of times a year — that's the scenario where the write-cycle limit can genuinely be reached within a few years. A casual photo camera card, which fills up gradually and empties occasionally, accumulates far fewer write cycles per year and in practice rarely reaches its technical limit before becoming obsolete for other reasons (insufficient capacity, physical damage, loss).
Data retention: the other kind of "lifespan"
There's a second way to measure durability, separate from write wear: how long a card that's no longer actively used retains its data. The industry standard (JEDEC JESD218) requires consumer flash memory to retain data for at least one year after being disconnected from power, under normal temperature conditions — which is why it isn't a great idea to keep an SD card as your only long-term backup without checking it periodically.
How to extend your card's lifespan
Avoid keeping the card constantly filled to 100% (leave some margin so wear leveling works better), format the card in the camera instead of on the computer when possible, and back up important content regularly instead of relying on the card as your only permanent storage. You can calculate how much capacity makes sense for your use case in the capacity by device guide.
Verifiable sources
Write cycles by memory type and data retention standards come from flash memory industry technical specifications, documented by JEDEC, the organization that standardizes memory specifications across the semiconductor industry.