Just like CDs and DVDs, using re-recordable media makes the lifespan of your data decrease significantly. You might even see the results of this now if you try to play a CD-R you burned in 2000 or so. So, if there are documents, photos, or anything else you want to last a while, I recommend he SanDisk SD Worm. This 1GB memory card lets you put data on it once, but that data is expected to last 100 years without degradation. It will be useful for legal matters as well. My question is — what device is going to read this type of data in 100 years? It’s available now, but only in Japan — sorry folks.