Quote - If it is a scene with a lot of motion, say someone running and the camera is moving, you do not need the max resolution. The frames with action that fast will tend to blur together when viewed, and max resolution is not needed. Putting a detailed primer scene right before it will make the person watching it think they are still seeing all the detail in the scene, but it isn't really there.

There are also scenes that will be rendered at high resolution, but use motion blur when rendering. That could be a scene with a lot of motion in the foreground, the camera is not moving, but other things that are being rendered in the background are not moving.

Planning all of this out with a simple script will save you a lot of rendering time.

It's not just resolution: the type of rendering you do can be optimized.

For instance, in a scene with a lot of fast movement, say a scene on a street with vehicles going by, you don't really need to have proper reflective glass (simple transparency will do), or even a proper reflective finish on the cars: a fake reflection map could work just as well. You might use shadow-mapping (if it's faster) than raytracing, and so on and so forth.