Originally posted by psoo I wonder if it's worth the time and trouble to use anything but AWB.
Most of the time AWB makes sense as a default. However, I can think of at least four reasons for shooting in manual WB:
a) Multiple shots to be collaged into a panorama: It's a pain if your sky is shifting color balance, so for any sort of merging or stitching shots, use a manual WB.
b) Portraits with artificial lights: If you're shooting in the studio, you don't want the skin tones to change because of different colored clothing or decor or environment. If using flash, or tungsten, or daylight balanced LEDs, then manually set it to the light source WB.
c) Intentional wrong WB to create a mood: Under exposing and setting WB to tungsten in daylight shade will give you a very cool blue balance. Yes, you can do all this in post, but shooting it that way intentionally may lead to better shots and more exploration with that incorrect setting. Conversely you can get a sort of an Instagram yellow opposite of the earlier example while shooting in tungsten light and manual WB set on shade.
d) Catalog work: Whether for commercial cataloging or scientific in a studio or lab, I'd set it to manual (of whatever light source is used) for consistent white balance.