Memory Card Lifespan

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Today’s Question: A question to which I can’t guess the answer: I have a 64 GB memory card. I take the images, download them into Lightroom, then I put the memory card back in my camera and format the card. How many times can I format the card before it is time to use a new card?

Tim’s Answer: I suppose part of the reason you’ve not been able to find a clear answer to this question is that there isn’t an entirely clear answer to begin with. But that doesn’t mean I can’t provide at least some basic guidance that will (hopefully) prove helpful.

There are a few things worth understanding here.

First, since the question specifically relates to formatting the card, we’ll start there. With most cameras the act of formatting a digital media card has a very minimal impact on the life of the card. The reason for this is that in most cases formatting the card doesn’t actually do very much.

Yes, I realize that when you format a digital media card in your camera, all of the photos disappear. But in actual fact, with most cameras the images are not truly erased, but rather the “table of contents” for the card is updated to indicate there are no files on the card. This is why it is possible to recover “lost” photos from a card, as long as the photos that were deleted (or erased by formatting) have not been over-written by new photos (or other data).

So, formatting the card has a very minimal impact on the life of the card.

Next, it is important to understand that the lifespan of a flash memory storage device (which is the category most digital media cards fall under) is limited based on an approximate number of read/write operations. You can essentially think of the individual storage components on the card as being something that wears out, although that’s a significant over-simplification of what’s going on.

The expected lifespan of a given card depends upon the specific components used for that card, and can vary wildly from one manufacturer or product line to the next. Some cards are estimated to be able to handle around 100,000 read/write operations for each “unit” of storage space, while others might have a life expectancy on the order of perhaps one million read/write operations. And, of course, it is important to keep in mind that these expectations are presented as a median expectation, so your results could of course vary considerably.

Finally, we have to take into account that today’s media cards are “intelligent” about how the storage is used. This includes, for example, a form of “load balancing” where the card will vary where each new file is stored so that each individual unit of memory will have about the same amount of use as every other unit of memory on the card. Also, as parts of the card start to go bad, those areas are automatically taken out of service. This helps prevent data loss or corruption, and also explains why you might see the amount of available space on an empty card go down over time.

Putting all of these (and other) factors together, you can probably appreciate how difficult it can be to predict with any degree of accuracy just how long a given digital media card will last before it can’t be used. In my experience, for most high-quality cards, you are more likely to replace the card for a faster or higher-capacity card before the card actually fails. But, of course, some cards fail almost immediately, some cards cause data corruption, and some cards last much longer than you would ever expect.

Having said all that, you can use the information above to calculate some basic estimates of potential lifespan based on how many photos you tend to capture on a given card over an extended period of time.