My experience in this field includes thousands of images: from Coke-Cola lifestyle advertisements to catalogue products, to family photos. I am happy to be hired for any retouching work.
Retouching and colour correction come in a variety of levels, and there are four basic schools of thought. In my personal work I adhere to one of these schools, but it's not uncommon for a client to want another one of the avenues applied. I have listed these at the bottom of the page.
I have been going through my old family photographs and digitising them for our future family generations. I felt it was important to get this done before the real photos were too far damaged.
If this is something you would like a quote on for your collection, or perhaps you just have one or two that need restoring - let me know.
This image of the Queen of Muay Thai, Julie Kitchen, has had a few styles of retouching applied.
To start with, the obvious colour correction and colour blending is apparent. I have removed any blemishes, but kept the skin texture for the natural feel.  You may also notice that I de-emphasized a couple of the small lines on Julie's side. Some people frown upon this practice, I only do it if the model asks. Even then I try to de-emphasize rather than remove.
Finally, I used a practice that is standard for clients such as Coke.  A keen eye here will spot that in each shot, her feet are different, as is her right hand and her left leg. Her hand and front leg is from a completely different photo. The back foot has been retouched to that shape. Overall I felt these changes gave a nice compositional balance to the image. I don't often do this for my own work though, but here it works.
I included this image of world famous female fighter Lena Ovchynnikova as a I felt it was a great example of what professional colour correction can do - how far an image can be pushed and pulled.

In this shot I have gone for the natural retoucing style. I have removed a few blemishes and completely kept the skin texture - including Lena's scar on her chin.

Four schools of thought
Limited/Natural retouching
This is the one I use in the majority of my own work. Skin blemishes are removed as are dust and scratches. Other natural human things are not touched, ie: moles, wrinkles, weight etc. These things are an important part of who we are, keeping them as they are is the natural thing to to. The beauty with this style is ideally the viewer will not think about what work has been done, rather they will just think it's a good image.

Full retouching
In some cases I have been asked to make someone look younger (none of us are pleased to be ageing!), I have been asked to reduce someone's weight or fix hair and the like. It's all possible. It has is applications. Some people like it, others do not. This style of retouching is actually easier than the natural style above. Quite often people use this style, and it usually leads to the viewer's first thought being "has this been retouched?". In my view, defeats the point.

Quick retouching
This is extremely common and used mainly by wedding photographers who have a large amount of images to retouch. The level of retouching isn't very extensive, but it does the job. Having a full wedding album professionally retouched would cost too much for anyone.

Anything goes
If you can conceive it, it can be done. Backgrounds change, limbs change as does anything else. This is sometimes called photo comping, or compositing.
It's not uncommon for some images to use a combination of some or all of the above styles.