I have far too many chess books. I have far too many chess DVDs. But whereas I have far too many unread chess books, I have at least watched all my chess DVDs, some more than once [Ed: Not quite true, I bought two more this week]

The majority of my DVDs are on openings. They fall into different categories.

1. Openings I'm not intending to play, but watch for instructional value - e.g. Kasparov's DVDs on the Najdorf and QGD. Just watch these.

2. Openings I've never player or played a long time ago but might like to try out. e.g I played the French for many tears, but stopped over a decade ago so watched Zielgers DVD to see if I could be tempted back. I watch these, try them out on the Internet, then try work out a repertoire I like. So far the only one I've taken up into my main repertoire is the Ruy Lopez.

3. Openings I already play. Usually don't contain my repertoire choices, but can give me some more options. e.g. Nigel Davies Pirc DVD. 7 hours in this one  , and it covers 6. ...Na6 vs. the Austrian as a repertoire choice which is hard to find (most punt the 5. ...c5 which I've usually played) so that's another option incorporated into my repertoire for me now. Also, if I've not played for a while, I can watch it as a refresher.

My real opening study is with Chessbase and Books, so I think of my DVDs more for entertainment and inspiration.

One thing I like about DVD's, besides the fact that I learn better from audio/visual input than from reading, is that you can watch the whole thing faster than reading a book, so repeat viewings don't take as long to study the material over and over. 

My usual approach is to watch the video once in its entirety to get the general ideas about the opening, knowing that I won't remember most of the details. Then I watch most of it a second time to try and remember more detail. Then, depending on how often I plan to play the opening and how critical it is to remember all the moves, I might plug the DVD into my computer instead of my TV, and "take notes" by playing out the lines in a chess program, pausing the DVD as necessary, and saving a pgn afterward of the critical lines.

Overall though, repeat viewings and going back to look up specific lines as they come up in my games tend to be enough without the note on all but the sharpest of opening lines.