Originally Posted by Syb 
These are interesting differences in the responses above. I use the review mostly to check facial expressions. I take a lot of portraits of people "in action", that is while they're addressing a speech for example. It is very convenient to see whether the expression was right when the shutter button was pushed.
When it comes down to other things, I use the LCD for histograms and composition. But this trial and error- way of working makes me - this is my fear - a slower photographer than when I would simply know what works and what doesn't.
Just the idea that I have that once-in-a-lifetime-opportunity to shoot that famous gorgeous rich woman because she walks by... and that I have to adjust-check-adjust-check-adjust-.... simply because I didn't train myself to do it right automatically.... it keeps me awake at night!
(so then I practice)
Cheers,
Syb
You should spend just a little time testing your camera and all the lenses you have, for exposure.
I find on the K10D especially that old lenses meter in a unique fashion, adding a TC even to a new lens modifies metering. you can learn how a camera and lens behave in less than 15 minutes with a series of test shots. Learn this, and plan in advance, the camera is predictable, as long as you have measured its performance in advance.