Good point about CDs. They do degrade over time, as do DVDs. You don't really notice it so much on audio DVDs as they are designed to play even with significant losses. I still have the very first CD I ever purchased (Dark Side of the Moon), and it plays fine without noticable issues, though it's probably more than 30 years old now.
However, data is a different story. First, the process of burning a CD is somewhat different from the techniques used on mass-produced audio disks. It has so far shown itself to be more succeptable to aging than audio disks. So, if you're going to store stuff on disks you burn yourself, I'd strongly recommend that when you do so that you make at least 2 copies. That way, if a single file on a disk is corrupted, you can most likely recover it from your secondary copy. As time passes, and tech advances, it's a good idea to migrate from old disks to new ones. Yes, it's a pain, but it will ultimately save you lots of heartache in the long run.
What I've done for my backups is to migrate from CD to DVD. (actually, with some of my data I went from Floppy, to CD, now to DVD). One advantage of this, in addition to refreshing the copy, is that you can generally consolidate as you go. One CD is at most 750MB of data, while a DVD can be 4.5GB to 8GB depending upon whether or not you use dual-layer disks or not.
If you have a lot of data, such as vids and stuff, which take up a lot of space, even going to DVD can leave you with a lot of disks to store and keep track of. These days, SD cards are pretty cheap, and provide some incredible storage capacities. As far as I'm concerned, the jury is still out on the longevity of these things, but I don't see why they shouldn't last as long or even longer than optical media like DVDs and CDs as long as they aren't subjected to extremes of temperature. (I've had micro-sd cards go through the washer and dryer and not had it affect them as far as I could see. (though I wouldn't trust such a card for long term storage).
Finally, since hard drives have gotten so cheap, for insane storage capacity, they are also a viable medium for archival storage.
In all cases, I strongly recommend 2 copies of everything with a refresh of the data at least every 5 years. I keep one hard drive of my archives in a safe-deposit box so it's offsite and in a rather temperature-controlled environment.
I shudder to think of how much family history has been lost due to poor backup procedures. The same is true for governmental records. The amount of data NASA has lost because they can no longer read mag-tapes of early mission data is astounding.
That's the idea. At least 2 copies, preferably on 2 different types/brands of media. Murphy's Law applies, things go wrong over time. I've had old stored hard drives fail after trying to extract data. I've had a big box of photos get destroyed by water damage; the negatives stored with the paper photos also got destroyed. I waited too long to attempt digital conversion of old 35mm video but the nitrocellulose of the film degraded and rotted. And I've had CDs and DVDs fail. I do have audio CDs from the early 1980s and they still work fine. But the type of digital CDs that people burn themselves are for the most part poorly constructed.
If you place your media in a home safe, place it in airtight bags with those silica gel desiccant bags, because home safes contain a lot of moisture. Best to vacuum seal the airtight bags; the machines are cheaply obtained. I vacuum seal a lot of old stuff to keep it from rotting. SD cards and USB sticks are pretty reliable, but even then I've had USB sticks fail. So multiple backups on different media is a good idea.