The best way to deal with digital noise in photographs is to start with having a correctly exposed photograph taken by a high-ISO capable camera. Then digital noise mostly isn't an issue unless you start pushing the upper limits of what the camera is capable of. But sometimes (hopefully only sometimes), you have to deal with an under-exposed photograph from an older camera ... and then the digital noise becomes apparent. Then we have to use software to clean the image up.
For those times when I do have to deal with an image with Read more inside...