That's a great question George.
After playing hundreds of gigs out in the hot sun, blowing undersized circuits, getting seriously zapped by faulty ground wires, and playing on drum riser "postage stamp" sized stages, we put together a performance contract. In it we now include basic specs to be provided for our band including covered performance stage area, sound, lighting, and electrical requirements, whether the band will be fed dinner or provided drinks, load-in times, out-by times, dress code and acceptable payment methods so everything runs smoothly, no one gets hurt, and there are no misunderstandings.
Having answers to these common questions prepared in advance makes your life easy and gives the band credibility when things go right instead of wrong. For more on this google "Van Halen brown M&Ms"
DLR explains:
http://www.youtube.com/watch?v=YwHO2HnwfnA