There has been and always will be different opinions on how much retouching to do, if any, a good photographer should do. Some claim all shots are perfect out of their camera. Some retouch every shot and would never allow anything to leave their hands without adding their touch, their style. I do both. Sometimes I get way to artzy with a shot making it gritty, B&W, flip it, blow out the whites, whatever I feel to make it art that I enjoy. I always try to keep it beautiful and interesting.
But I think just about any image can use a little help only because to make it interesting it should look slightly better than real life. Real life is raw and unforgiving and a bit harsh. Adjusting the light after the fact to put more focus on the subject isn't a bad thing. My opinion.
Here is an example of a shot that seemed just fine...the original is on the left. I'll admit, although a bit biased, that this shot rocks. It was worth wading out in the stream and putting $5K worth of camera and lens within inches of a cold fast running creek. Spooky but you do what you have to to get the shot.
When I looked at the shot in Lightroom 4 I thought it looked just fine. Then I thought about what i could do to it to make it more powerful. Draw the person into the shot. One thing that always works and I like to do is to bring the light up on the subject and down surrounding them. It's a good way to focus the viewer where you want them to look. Lightroom 5 comes with that feature actually. I used NIK Color Effects Pro 4 and the filter is called Darken/Lighten Center.
When I'm not getting 'artzy' with a shot I rarely retouch it beyond what it MIGHT have looked like from the camera. I could have an even lighter hand sometimes but that comes with practice and constantly learning the tools I have.
So, if you are one of the folks who feels all of their shots are 'dead on perfect' good for you. Ask yourself if there is anything that could make them just a touch better. Or ask yourself if you don't retouch because you don't want to spend the time to learn what it takes to do it well. It would be a shame if that were the case considering how much time a photographer and model(s) spend to get the shot.