A photograph can completely change when you change it to black and white. A color photograph must take into consideration how the colors in the image will compliment one another. A black and white photograph must take into account how an image will look without color. A great color photograph can be a great black and white photography, and vice versa. But, sometimes a good color photograph lacks intrigue without color and a good black and white photography becomes a mix of color confusion when changed to color.
Some people shoot exclusively in either black and white or color. I’ve found over time though that even before I hit the shutter button I know an image will be more powerful in black and white or more powerful in color. I try to challenge myself by using both. Some days I’ll try to shoot just in black and white. Sometimes though, it’s not until I start the editing process that I second guess my decision and realize I should switch how it looks. And sometimes I just can’t decide.