How often do you dodge & burn, particularly in Photo-shop, and to what degree?

I'm reading an interesting article (during work ) illustrating the use of D&B to adjust exposure in areas to increase contrast to liven up dull/flat images; dodge highlights and burn shadows.

I'm assuming the opposite is recommended to reduce contrast as well; dodge shadows and burn highlights.

I guess my question is are these tools better used to decrease contrast or increase contrast? What are your experiences.

If some can provide images as examples, all the better.

Thanks in advance for all replies/insights/recommendations.