[jatrax]

In general and especially in film days... we are taught to expose to the right (ETTR) a bit to get some shadow details that otherwise you would not get.

I use the exposure compensation button for all images I take. It's a quick way to adjust the exposure without changing any of the settings.

On the k-5/k-5IIs I used my own version of ETTR, which I call "ETTR as far as you can". I don't know if it is any different and I'm sure there are better ways but what I do is take a test shot with the 'blinkies' turned on. Then using the EV comp button I dial up the exposure until I have one or two tiny red blinkies in areas that I know are all white, usually the brightest spot in a cloud. Not a big area, just a couple pixels. That tells me I have exposed as far right as I can without losing important detail. Those couple of pixels are not needed or noticed and serve as a white point for the whole image. That method is quick and dirty and I know some will cringe but it gives me good results without a lot of fiddling.

However, on the K-3 I rarely use the EV comp button except on scenes that are going to fool the meter anyway, like snow or white buildings.

I never assume the meter is correct, I think you should be adjusting so that your white area is white in every image. If you get that correct then the rest of the image falls into place within the limits of the dynamic range of the camera. That's part of the photographers job to get right.