Labels on CDs are a potential problem. Many of them that don't warp the CD tend to "stretch" and raise bubbles in the label that can snag in the player/reader¹. I've seen no indication that the better quality labels cause deterioration of the disks themselves, although I can't rule out the possibility.

¹ Many pressure sensitive labels run right out to the edge of the CD, and quite a few common "music CD players" - especially portables and vehicle "dashboard" units - apply a "damper" to minimize bouncing around while the CD plays. The damper is often just a small felt pad that rubs on the outer face of the disk. Any bubbles, buckles, or frayed edges on the label may make the disk "unplayable" in a player of that kind. A "proper" label for disks to be used in this kind of player would leave a bare rim about a quarter inch wide, but I haven't found any like this.

For archiving, a common recommendation is that no labels should be used, with each unmarked CD in a case with an acid-free label on the case. This could theoretically be a manageable method for the extremely anal-retentive administrator where no one but the person in charge ever has access to the archive, but for most people the CD must be marked in some way.

A felt-tip marker and a simple disk number may be sufficient for data CDs and maybe for archived music CDs - if you keep a complete and accurate index of any information you need about what's on them. You may still want paste-on labels for your "playable" music CDs, but those can be replaced as needed from an archive CD that doesn't really need a detailed label.

If you want to be extra cautious, a felt tip "number" can be placed in the hub area, or for a "less than full" CD, around the outer rim. (CDs play from the inside outward. With careful examination in a good light, you usually can tell where the "recorded part" ends on the disk so that the markings can be made where there's no data.)

For data archives, a list of the files on each CD is, for my purposes, sufficient, so after the CD is burned I try to immediately, at a command prompt, go to the folder where I keep the index files. I would see a prompt like C:\CDIndex>

From there, with E:\ as the drive containing the CD, I'd run:

DIR E:\*.* /s >filename.txt

This puts a text file containing a list of the files on that CD in my index folder.

For the filename, I'd use the "CD Number"+a brief description of the kind of data, like "1048_emails_080120.txt" (for emails archived yesterday).

With ALL of the CD index files in one folder, Windows Explorer can fairly quickly find a particular file name, and the number that's part of the CD index file name tells me which CD to pull out.

Text index files for 250 CDs would likely run less than 30 MB, which is pretty small for a CD, so if you feel like it you can add the whole index folder to an occasional CD, along with whatever else you're burning, and have an updated archive of the index as it grows.

Different methods probably will be needed for backups that contain more music/video than data, so each archivist will need to do some serious thinking about "what's sufficient" vs "what's possible."

"Who's gonna care enough to look at it when I'm gone" may also enter the archivist's planning too.

John