Keep in a memory case or whatever that can prevent direct contact to skin whose moisture can tarnish contacts and other surface material that produces or gives out electrical static that will cause corruption to your files. I have seen some who save save or just want to not carry a bag would put spare card in shirt or jean pocket without a case imagine if you sweat or fabric rubbing constantly to cause static. I also will mark each card including the date I stated using them. these gives me a timeline as to how I have used that card. This gives me a time period to note when there may be possible failure occurring to the card. By numbering them, I get into a habit of rotating them for use. Thus stretch out their life span over a long period. Base on the way I shoot, I can over time it takes about 2 years for my 16gig cards, longer for larger cards..eg to start showing signs of failed write. Why take risk with photos you may treasured? It's not how good the brand of cards are alone but as important is as how you look after them to keep them working too. There is that logic among especially newbies, that the largest card you can buy is the best well to go so you don't have to carry so many or keep so many troublesome cards, it might be true but depending on how often you use the cards and cared for them, anything go wrong you can say goodbye to whatever was saved to it and get home to full or partial corruption to the photo files.. No double slot in your DSLR? Then try using more cards then higher capacity ones. I have most of my card in 16 and 32gig I see no need to go even 64gig. even shooting in RAW 80% of the time I don't see it as troublesome to be changing my cards often. Smaller card size ensure I at least don't go home losing everything I shot that day or over a period of days with that same card in the DSLR.. And 'often' is like mostly hours apart. If that is too much work for you, I don't know what to say to this type of person heh.