You can save significant render time if you understand how rendering works. In this 10 minute video, James Crowther explain how to optimise rendering through detailed knowledge of the cycles render engine's light paths settings.
You'll learn how to set the right number of bounces for your scene to balance how the scene looks and how fast it renders.
In the demo scene I saved 20 seconds of render time, a saving of 27%, the original scene taking 1 minute 50 seconds before optimising, and one minute 30 seconds afterwards.
