I only have a double, so don't have a lot of choice!
To be honest, unless I'm on a long stretch of flat, or a rising hill, I'm always swopping and changing between the two chainrings.
I used to be of the opinion that I worked through all the gears of one chainring before moving onto the next!
No, no, no, no, no!
My constant twiddling works great for me, because now I rely solely on cadence, speed and momentum - I go by how it feels, rather than what I think I should be in.
Switching from one to the other and back again allows me to get a much better ratio of gears (I have 18 instead of 9!), keep my cadence steady and achieve a much smoother transition up and down the gears.

I know it's slightly different for a triple because the gearing ratio is much lower - but for me the principle is the same (my hybrid/commuter is a triple).