I am a professional computer nerd by day... unprofessional music nerd by night... I can give my opinion about the different options for archiving.
As far as affordable and easy-to-find, HTL (high to low) BD-R discs should be the best option. They use inorganic layers (copper + silicon) which get fused together by the laser when you burn. It should be immune to light and environmental factors and last a long time. The best ones I have found at a good price are SmartBlu brand. They are less than a dollar for a 25GB disc.
Most CD-R and DVD+/-R discs use synthetic organic compounds for the burning layer, which means light, temperature, humidity etc. will cause it to degrade over time, and it also degrades on its own regardless of how well you treat it. The factories that used to make those discs switched to making LTH (low to high) BD-R discs which also use the same organic materials in the burning layers. (LTH BD-R discs are also the cheaper and more common ones).
A company called MAM-A (formerly Mitsui) specializes in archival-grade discs of all kinds. They literally use 24k gold for the burning layer on their discs. They have been around forever and are usually considered the best quality brand. They claim their discs last longer than any other storage format, other than paper... I think they are usually a few dollars per disc. If you can afford it that is probably the way to go.
There are also special DVD's called M-Disc which claims to last 1,000 years. The data is burned into a rock-like layer. They claim to have done all kinds of tests like dipping the disc into liquid nitrogen and it still works after they thaw it. They are hard to find and you need a special drive to be able to burn them. Their website has too much "Salesman speak" for me... I don't know if I really believe their claims. Check back in 1,000 years and we can find out...
Hard drives are hit and miss, because they are made up out of mechanical parts and circuitry they will fail randomly. And the discs themselves are magnetic which can fade over the years. I have some old floppy discs from the 80's which still work and I have a hard drive that was just made this year and it already crashed. So you never know. I use a USB hard drive for making backups of my computer every couple weeks, just so I have something backed up in case my computer dies, but I wouldn't expect it to work in 10 years.
SSD, USB flash drives and memory cards can get zapped dead by the slightest power surge or static electricity... and sometimes they just go bad for no apparent reason. They are fine for every day use if you have backups, but I would not trust them for any long-term archival storage.
Computer backup tapes are flaky and I never had good luck with them... The backups they do at work are always failing because of the tapes being bad. You usually need to use special software and finding a computer with a working tape drive and that same software 10+ years later is probably going to be difficult.
Not that I am good about doing it myself... obviously... but if your data is truly irreplaceable and important you should make at least 2 different backup copies onto different formats of media. And probably re-copy those copies to new discs (or whatever you are using) every 4 or 5 years just to be sure they aren't going bad.
As far as affordable and easy-to-find, HTL (high to low) BD-R discs should be the best option. They use inorganic layers (copper + silicon) which get fused together by the laser when you burn. It should be immune to light and environmental factors and last a long time. The best ones I have found at a good price are SmartBlu brand. They are less than a dollar for a 25GB disc.
Most CD-R and DVD+/-R discs use synthetic organic compounds for the burning layer, which means light, temperature, humidity etc. will cause it to degrade over time, and it also degrades on its own regardless of how well you treat it. The factories that used to make those discs switched to making LTH (low to high) BD-R discs which also use the same organic materials in the burning layers. (LTH BD-R discs are also the cheaper and more common ones).
A company called MAM-A (formerly Mitsui) specializes in archival-grade discs of all kinds. They literally use 24k gold for the burning layer on their discs. They have been around forever and are usually considered the best quality brand. They claim their discs last longer than any other storage format, other than paper... I think they are usually a few dollars per disc. If you can afford it that is probably the way to go.
There are also special DVD's called M-Disc which claims to last 1,000 years. The data is burned into a rock-like layer. They claim to have done all kinds of tests like dipping the disc into liquid nitrogen and it still works after they thaw it. They are hard to find and you need a special drive to be able to burn them. Their website has too much "Salesman speak" for me... I don't know if I really believe their claims. Check back in 1,000 years and we can find out...
Hard drives are hit and miss, because they are made up out of mechanical parts and circuitry they will fail randomly. And the discs themselves are magnetic which can fade over the years. I have some old floppy discs from the 80's which still work and I have a hard drive that was just made this year and it already crashed. So you never know. I use a USB hard drive for making backups of my computer every couple weeks, just so I have something backed up in case my computer dies, but I wouldn't expect it to work in 10 years.
SSD, USB flash drives and memory cards can get zapped dead by the slightest power surge or static electricity... and sometimes they just go bad for no apparent reason. They are fine for every day use if you have backups, but I would not trust them for any long-term archival storage.
Computer backup tapes are flaky and I never had good luck with them... The backups they do at work are always failing because of the tapes being bad. You usually need to use special software and finding a computer with a working tape drive and that same software 10+ years later is probably going to be difficult.
Not that I am good about doing it myself... obviously... but if your data is truly irreplaceable and important you should make at least 2 different backup copies onto different formats of media. And probably re-copy those copies to new discs (or whatever you are using) every 4 or 5 years just to be sure they aren't going bad.
