Yeah, I know this was a different century but for most of my gigging life the average gig was from 9pm to 1 or 2am. 45 min sets seperated by a "short call for (copious amounts of) alcohol". The end of the gig was followed by 1) a trip to IHOP for a 3am breakfast (if we were "unlucky") or 2) a long night of "partying" if we WERE lucky. This pattern could be repeated 3-4 nights a week. We lived like vampires and just the thought of playing a second gig during a 24 hour period would have us throwing up (which we were probably already doing).
Obviously, to be able to play 2-3 gigs in a 24hr period and still have time to practice, telemarket yourself, browse the net, kiss the wife, feed the dog, etc., requires that one live an exceptionally clean and wholesome life. However, us old guys know that this is not only counterproductive to the creative process, but goes against everything we musicians stand for. Damn, I hate progress.
BTW, you can check the accuracy of the above with any of the old geezers on this board, at least those who can still remember the "good ol' days".