There is a very important procedure after saving in a CD or DVD, check the CD!!!!
A burned CD is not always correct even when the CD burner reported that it was burned OK, the failure rate is small but exist.
There are some free utilities that allow you to compare the content of a CD to hard-disk, I use CdCheck.
If your content are zip files you have the alternative to test the zip file on the CD.
If the check failed even in few files you have to burn another CD and discard this one.Another symptom of a possible future problem is when the check process become too slow reading the CD content, the CD can be OK but by some reason accesing its data is more difficult and you have the risk that this problem will increase with time turning the CD unusable, so burn another CD!!
Another measure is to classify what you backup in order of importance.
There are some item that when you lose them nothing important was lost, so burn it on a CD.
There are items that are important and you cannot lose them, burn two backup copies and store them in different place.
There are item that if you lose them you die, burn three backup copies and store one copy in your mother's house or somewhere else.

Quote - That's very good in theory, and probably works great for disciplined folks. I even tried to do that once myself, but kept saying "oh, I'll use that tomorrow".

Don't think that I have good discipline, my live anthem is:
Why I must do it today if I can do it tomorrow?,....and tomorrow never comes.....

Thta is why a small partition size is important, one day I have to make room for new stuff and if I don't make more room I cannot add something, so the size remain always small and the entropy never increase.

Stupidity also evolves!