After finishing shooting for the day, you need to figure out how to keep your memory card safe until you transfer your images to your computer. The worst thing you can do is put the card in your pocket and taking a risk of losing it. A better solution is to have two memory card wallets—red and gray.
Red means “Don’t touch”
Take the card out of the camera and place it backwards in the red card wallet. Placing the card backwards will help you remember the card has photos on it and it is not to be used. Your memory cards are safe in your “Red—Do Not Touch” card wallet, ready to be transferred to your computer.
Gray means “Safe to Use”
After you transfer your images to your computer, format the memory card in your camera before the next shoot. This will avoid any confusion when you’re ready to shoot. If you have multiple cards, format each card in the camera before you place them face up in the gray card wallet.