Photos: format your camera rather than deleting individual images - computer systems and deleting directory pointers vs memory chunks

Let’s pretend for a moment that your memory card has a shelf-life of 1,000 uses. Let’s say that you go out and take 500 photos, that’s 500 uses on your memory card. You then upload the photos to your computer, and then individually delete each photo using the delete button on your camera. Deleting each photo individually counts as another 500 uses on your card. So in all, you’ve just spent 1,000 uses of your memory card, leaving you with no uses left on that card. Now, let’s pretend that you’ve uploaded your 500 photos, but instead of deleting them with your delete button, you use your camera’s Format function. Formatting works in a different way than deleting, and only deletes the directory files rather than the images themselves. This then allows the images to be overwritten the next time you take a picture. Because of this, formatting only counts as ONE use of your memory card, regardless of how many photos you’re deleting. So, in the scenario above, you’d have used only 501 of your memory card’s uses, as opposed to 1,000 with deleting manually. Certainly, memory cards available today will be able to handle far more than 1,000 uses, but the illustration still rings true – formatting your card causes less wear and tear on your memory card than other ways of deleting images. Additionally, because formatting only deletes the directory file instead of the images themselves, images on a card that has been formatted are typically much easier to recover (if needed) than those that are deleted manually, assuming that you did not overwrite them by taking more photos. Not a bad trick to have up your sleeve in case of emergencies, am I right?


source: http://digital-photography-school.com/the-best-way-to-delete-photos-from-your-memory-card/