Portraits must reflect the inner essence of a person, working with light during the shooting and adjust in postproduction some minor spots unless it’s requested otherwise. Black and white accurate conversion is a favorite retouch for clean and conceptual images.
A picture with too many dirty spots can be distracting, especially when it’s showed in small devices or the web, removing scratches, and semi hidden objects along with bringing back some details in the shadows helped with the high contrast light of midday to improve the overall look of the elements.
Nobody likes a dull picture, a little help can make a picture pop, the sky intensity must be vibrant and white elements must be white, removing minor dirty spot will make the reading of the image easier.
Product photography requires the most clean pictures, not a crumble could be out of place, everything must be spotless, lights are easily adjustable in a studio environment and there’s plenty of time to set up the composition of elements properly, but sometimes some piece needs to be beautified a little bit.
Plastic or rubber look and eyebrows removal are available upon request, but removing a dinosaur from a picture is unacceptable, too much is too much. [Disclaimer: I’m not the copyright holder for George’s original photo, but I’m kinda good friend with Nessie]