I would say all prints need to be spotted.
You need a fine brush and spotting dye similar to Spotone.
I like to work with a small palette that has 6 dimples, and I mix the Spotone in different concentrations from dark to light. I make hundreds of little droplets on the palette and allow them to dry out. Then each droplet becomes a "charge" for the brush. I dampen the brush, draw it across a dry droplet, then draw the charged brush onto a test strip to see what tone it is.
Then I hunt the print for a spot that needs to be that tone and dot it. Sometimes a brush charge is good for several spots. Sometimes it only works for one. Sometimes its a dud and nothing happens.
Most of my prints have a spot that is futile, the best I can do is to make the spot "less apparent" from a distance, which ultimately is the goal (to reduce distracting the viewer). Sometimes though, the spot disappears so well that you cannot see it when you go back to it later.