I just saw a documentary on TV of a Chinese who came to British Columbia Canada about 1910, and worked as a houseboy, fur trader, gold miner, storekeeper and photographer in the central interior of B.C. He died in 1973 at age 90, a fairly wealthy man. His photographs were mostly portraits, of the native, Chinese and white populations of the area - cowboys, miners, businessmen and their familes. Before he died he gave 1400 negatives to a local historical society (Barkerville), where they lay forgotten until 1995, when someone found them and realized their historical significance. They didn't describe his camera, or even the format. Most of the photographs on the show appear to have been taken between about 1913 and 1930.
Some of these negatives would be over 80 years old. It got me wondering if there was any chance digital files would survive that long. The two things against that happening would be (I think) that the storage medium would deteriorate and the equipment to read the files would be gone. Apparently the negatives were stored in a leather suitcase in his basement after he retired.
It also got me wondering if any of my negatives will last that long!