Eventually, all my files end up archived on DVDs. A few years ago I was laboriously typing summaries of each disk into an Excel document, so that I could find files again if I needed them. What a hassle!
Then I came across a terrific little app called "Cathy". It's a free download from the developer's site here (towards the bottom of the page).
It's simple, fast disk cataloging software. Immediately you burn a disk, you just run it through Cathy, and she takes a comprehensive record of all the files on the disk, and adds it to her library.
Then, it's super-simple to search the catalogue for keywords, or dates, or whatever, and Cathy shows you which disk/s contain your files.
If you don't have a system like this to track your archives, I strongly recommend one.