In all photography, but especially people, retouching is as much of the image as is taking the photo. Every model I have worked with has needed some retouching, some less than others. If you have less than perfect skin, or have scars, stretch marks, small tattoos or a few extra pounds these all can be removed in Photoshop. 

All of these women are beautiful - however retouching allows for improvement. Note the change in the eyes, the adjustment to the bodies, skin and teeth. 

All of these examples are "rollovers" meaning that you can roll your mouse over the image to see the original file or stages of progression. Some of them you can roll over to see the original or click to see the original or another variation. If you don't see the finished image, roll your mouse off the image area.

All of these are large files, meaning if you are on dialup it will take some time to see all the files.