It is amazing what you can do with two or three pigments. In this watercolor I used three pigments: cerulean/ultramarine blue and raw sienna. Leaving the white of the paper white was another benefit.
There is less clean-up when you use a limited palette and their seems to be more harmony in the overall picture.
Often a small study leads to a stronger composition and sometimes outdoes a finished painting. It is easy to paint the 'life' out of a picture with too much technical information and lifeless brush work.