macmeister said:

"My two earliest (and best) CDs are now mostly completely clear, and all files are irretrievable."

One more reason to have abandonware sites. Actually, what are the best and most endurable backup media? CDs, ZIP drives, floppys, hard disks, USB sticks?

What a pity! What did you do with your CD's Macmeister? My first copies of hard disk partitions from 1993 are in perfect condition still, and so are my even older magneto-opticals.
I would assume that MO's are rather secure storage media, but who knows how long the devices for reading them will last?

I've had a couple of CD go bad recently too. Annoying as their contents can't be found anywhere else online. Verbatim "DataLife" my ass...

I really should go through all my CDs and dump them onto a hard disk before I lose any more stuff.

What a big collection of very interesting software!
Could themacmeister please be so kind to provide links to the Mediafire site too?
The MG download links just give me error 404.

I went through all my ld CDs / DVDs (up to about 2003) and imaged them all to hard disk.

Can agree with all the posts so far, I've got some CDs back to my Apple CD300e in 1994 that are in perfect condition, others that were MacUser cover discs that are toast (so to speak), the Apple Multimedia Festival CD is a real shame.
So in general the CDs have done well, but in a cabinet of maybe over 1000 CDs and DVDs I've got some unusables.
Best tips for recovering stuff:
1. wash in hand-hot clean water with a bit of Fairy liquid. Dry gently and try again.
2. Try a different CD / DVD drive, perhaps an older one. Current DVD-RW drives are £30 because they're primarily junk.
3. Try OS X Terminal to copy as many files off the CD as possible.

I only can second that, try to recover your CD's with your Apple CD300, if you kept it.
Its a SONY after all, with a 1bit error correction mode. I managed to recover a few disks being absolutely unreadable with "modern" drives.

@themacmeister:

I have not kept my CD backups in good condition, and I have payed the ultimate penalty.

Well thanks for posting up what you could, all the same
I know the meaning of loosing collections to time also. When backups of backups may be the only possibility, if I'm lucky enough to have been so organised at the time...

Really, even making two copies of every CD/DVD would have done it, as the chances of the same file( failing on both copies would be pretty slim. I guess when you burn stuff off, you're never sure if you're really going to need it in 10 years time.

Hard disks is where I'm at right now, especially with the low cost. Is anybody still using MO?

I've had a few go as well. Doubtless we all have or will sooner or later. From what I understand, the difference in life will vary from one manufacturer to another. Unfortunately that isn't the most useful information as every brand of blank CDs and DVDs is sourced from multiple manufacturers.

If one is starting to develop read errors it may be helpful to try reading it in a different drive. I have been able to slowly pull data off of a dying disc using one drive despite it being totally unreadable on another.