When making and experimenting with color schemes in Illustrator, I usually use a few base hue values (H) and start playing around with saturation (S) and brightness (B). Since I like similar value in my colors, I like trying identical S/B values for the different hues, but I have to change these values one object at a time.
Is there a way to select multiple objects, each with different hue value, and set saturation and / or brightness at the same level for them, while retaining the original hue?
One easy method is via Live Color or Recolor Artwork in Illustrator.
If you select a range of object and then choose
Edit > Edit Colors > Recolor Artwork you will bring up the recolor dialog box.
From the tabs on the top choose the Edit tab, then click the Link Colors chain icon in the middle center of the dialog:
Then set the sliders to HSB:
You can then adjust the Saturation and Brightness sliders while leaving the Hue slider alone to uniformly alter all selected objects without changing their starting Hue.
When you are done, simply click OK and your objects will be recolored with the new values.