Windows paint message

Is there a way I can detect the windows paint message to know that my Window needs to be redrawn? Maybe an Event that I can poll for?

I am writing a Windowed program and would like to not redraw over and over and use system resources if there is no reason to redraw the screen. So, I am wondering if I can catch the message windows sends that tells me a portion of my window has been uncovered or that my app was minimized and then maximized...

Thanks.