Question about battery life

It's essentially an instance of the law of diminishing returns. The amount of CPU life you 'gain' going from OPP4 down to OPP3 is much greater than going from OPP3 down to OPP2, and so on. Likewise, the amount of CPU life you eventually have to sacrifice to gain even a tiny amount of extra CPU ability gets much greater at the other end of the scale. This holds true for Overclocking as well as overvolting, although overvolting will have a more dramatic effect on CPU life than overclocking.
Sorry, I edited my post before seeing your reply. What about what the wiki mentions about "no clear advantage in slowing the clocks"?
When idle, the Pandora's CPU doesn't use a lot of power. A Pandora doing nothing clocked at 800mhz uses about the same power as a Pandora doing nothing clocked at 125 mhz.

A Pandora that's actually doing something is a different story.
With Full brightness, WiFi on and running... I do get consistent 10 hour battery life everything.