Mr. Vai revised his old 10 hour workout into a 30 hour one! Very interesting and helpful exercises in there! It's in the April issue with Joe Perry and Jimmy Page on the cover. [img]images/smilies/icon_jam.gif[/img]
I've got that issue, and really Vai excels on it. You can also download the samples and exercices he uses in this workout, you just have to go to the site of guitarworld and get them http://www.guitarworld.com/lessons/artists/0404.vai.php
you do "workouts" if you want your playing/technique/understanding of the instrument to get better . theres no way i would've learnt how to play jazz (half assed mind you) if i hadn't sat down and done some "workouts" scales etc and understood how they work