Hi Tigress,
Having worked in a club, I can tell you that, many times, DJ/bartending jobs are only 2 days a week. Most of the people at the club I worked for had 9-5 jobs. We called in occasionally when we were just exhausted and thought it would be slow that night. Fri. 13th is usually slow b/c ppl like to go out and find other stuff to get into. Usually, you have a back-up bartender for each (at big clubs) and a co-DJ and a back-up for them.
I can't slueth, but I can give my personal experiences. I hope this helps a little