It is said dvd's have a shelf life between 5 and 10 yrs.
micro sd cards have a life in excess of 10 yrs .
I would think dvd's are more likely to get damaged than sd cards
and if they have a shelf life of 10 yrs will they still have rom drives that will play them in 10 yrs time. will dvd rom go the same way as floppy drives.
In a past career i got a couple of organisations (large and very very small) through BS7799 Part 2 so although as you will of course know its moved on to ISO27000 series I still keep my hand in, especially in other management system standards so if you ever need anything related give me a shout (hope that doesnt sound too patronising, its a genuine offer )