If your getting memory probs rendering then its worth looking into as it saves RAM per part of your rendering, and it will save you a lot of time if your trying to do a "single shot" render, I use it to get the layers to comp final renders.
Its not strictly for animation or multiple scenes, although if you set everyting up right you will have multiple scenes for different parts of the render for which it will work perfectly!
"No pressure, no diamonds" Thomas Carlyle