$Nothing < $Something

I’ve done quite a bit of performance tuning in my career.  When people ask me about guiding prinicpals, the first one I give is always:

Nothing is faster than something.  So do as much nothing as you can.

After watching some GWT presentations, the Google guys were saying something similar, though I think less general and certainly with less flair. 😉

The fastest code is the code you never run.

I think this one principle is so useful, so generally applicable, that you can go far with just this one tool in your belt.