Memory card failure - not if, but when...
I vividly remember one particular self assignment in the eighties. I was at a nightclub where there was live music being performed. The rim lit sax player was belting out tunes to the mostly college student crowd. Not only was the music great but I was particularly engrossed in the stage lighting. I was shooting with my newly acquired Nikon FA loaded with Kodak Tri-X black and white film. I didn't have much money at the time so I had to limit myself to just one roll of film. The shoot went well and I exited the club and made a beeline for the darkroom where I planned to develop my film. I popped open the camera and to my horror there was no film in it. I couldn't believe what I was seeing (or wasn't seeing). From then on, I was particularly careful to check that my camera was loaded with film.
While most of us no longer (or ever have), shoot film, there are still valid concerns with today's digital cameras. Rather than film, today's images are saved to some sort of memory card. The memory cards tend to be very reliable but there is always the chance that images might become corrupted and non recoverable. For this reason I always try and head off any potential problems by purchasing name brand memory cards. Sure, there are great memory card buys out there, but in the end I would prefer to lessen (notice I said lessen) my chances for card failure by at least starting with a good card.
In the previous paragraph I used the word "lessen." Even when purchasing a name brand card, failure can occur. Take it from me, I have had name brand card failures in the past. Yes, it has been several years since my last memory card failure, but I have developed (no pun intended) the mindset that I might as well plan for failure and then have a game plan for what can be done next.
My game plan is to have PhotoRescue software installed on my computer. PhotoRescue is an inexpensive program that is available for Mac or PC. It is very user friendly and has enabled me to recover "lost" or "unrecoverable" images in the past. The recovery process does take time and you may find that not all images are able to be retrieved. Keep in mind that PhotoRescue is not the only image recovery program available but it's the one I use for now.
Finally, if you ever do have memory card problems then take it from me, it's best to just toss the card after attempting to recover your images. It's really not worth the money to keep a card that you no longer can rely upon for safe storage of your precious images. Most cards manufactured by reputable companies will come with a warranty. Keep those when you first open your card from it's original package. You just never know when you may need it for a refund.