> I disagree with 0.7 being the starting point for investigation on extraneous load, but you should be more worried about changes in 1st or 2nd moments in the load (velocity and acceleration), which as analogy on the link, you don't care too much about steady traffic, it's when traffic starts bursting at the seams.

Caring about 0.7 load means you've got some capacity left if traffic does burst. You generally don't have warning, so having a healthy amount of CPU left available is generally good.