Via Insty, more on robustness vs. efficiency.   

My take is that you can shoot for 100% efficiency for single processes or systems.  Just maintain an emergency supply of whateveritisium for when your system (inevitably) sputters.

As you begin to inter-relate systems, you darn well better have lots of spares, robustness, contingencies, etc.  When your program can be brought to a screeching halt…by a shoe…it’s time to trade quantity for assurance.