The ON-switch

Pages 30 and 32 of your manual. Questions like these can always be answered by reading the manual.

I believe we're talking about a miniscule difference of power usage here, between turning it on or off. Turning it on and off though stresses the switch innecessarily - I know it is tough, but it less likely to break if you don't use it too much.

the original topic was about the 'on' switch and what each setting does.

My normal shooting situations, I leave it on pretty much 24/7 and usually go days without having to recharge a set of batteries. And, I'm always ready to shoot.

I never turn mine off. It sits in my bag waiting for my initial press of the fire button and then it faithfully and very quickly, turns on.

I have left it set on the 1 minute to power off setting and that seems to work great!

The battery never seems to run down.

I usually only turn mine off to change lenses or to remove the memory for d/l'ing. Batteries seem to last for ages. I typically only have to recharge my 20D batteries every 2500 or so images...but I always use them in pairs. Haven't gotten any long term data on the 1D mk II yet.