Treatment of LCD's when there is an interuption in usage?

[mattw]

What are the guidelines when using LCD's and there will be a known period of non-usage during a session? Specifically, at what point do you turn off the monitors? What is the recommended time for the screen saver setting? I would think there is a max +EV point somewhere between turning them on/off every 5 minutes and letting the run for an hour with no usage.

TIA