One of the big concerns people have is that the media will die and they won't be able to read it. They will end up with a format for which no drive exists that can be used to read the data.
That is not as likely as it might seem. This is especially true if it is something that is widely deployed, such as CD or DVD. Even magneto optical is pretty common and has been deployed fairly widely in the medical field. There are MO archives that are very large.
Firms exist that specialize in recovery of data from obsolete media. If you have nine-track data tapes, there are firms that can read and transfer them. If you have quad video tape, there are firms that can transfer it. 8-inch disks, mini tape data storage from a commodore, Sinclair ZX Microdrive etc. Believe it or not, there are companies out there who have the capability of reading it. Even those weird formats that were failures, like the Castlewood Orb or Sony HiFD or the Pocket Zip. yeah, there are data recovery places that maintain the equipment to read them.
It might be expensive, though. Sending out some of those disks to one of the few places that has the equipment could be more than one hundred dollars per cartridge.