Hugely more important is TUNE YOUR SAW. Learn to tune by ear, and tune your saw to your mix ratio, whatever it happens to be. As long as you're running an oil and mix ratio that meets manufacturer specs, tuning will have a thousand times more impact on the life of your saw than the exact oil or mix ratio. Everyone running a saw should know how to do this, and how to check tuning, and how to hear incorrect tuning so it can be fixed immediately. Takes two seconds while cutting to make sure it's burbling out of the cut and cleans up in the cut. Don't bother looking at the plug, if you go too lean you'll burn up your saw long before the plug looks different. [links]