Dhl93449 - Taiyo Yuden guarantees 100 years. The issue is dye. Long lasting phthalocyanine dye (Mitsui Gold, Mitsui Silver) is more expensive than cyanine dye and can last 200 years on gold but is more sensitive to light and laser power variations. Cyanine dye is by itself unstable and has to be stabilized. I'm not sure what Taiyo Yuden uses but they invented CD-R technology and are known to be very reliable and long lasting. I went thru perhaps 500 Taiyo Yuden CD-Rs and never had bad one or one that failed. I have many about 15 years old CD-Rs working fine.
As for hard drives - I might be very lucky but I had only one disk failure at work and one at home (laptop) in last 25 years. Currently I'm running 6 hard disks at home and 2 at work for many years without any problems. In addition to these 6 drives I have two backups - just in case. Very often people who have failures are more likely to write but even then my drives (Fantom G-Force) have pretty good review. As soon as prices of SS drives drop down more I'm getting one for music storage.
As for hard drives - I might be very lucky but I had only one disk failure at work and one at home (laptop) in last 25 years. Currently I'm running 6 hard disks at home and 2 at work for many years without any problems. In addition to these 6 drives I have two backups - just in case. Very often people who have failures are more likely to write but even then my drives (Fantom G-Force) have pretty good review. As soon as prices of SS drives drop down more I'm getting one for music storage.