As an artist, especially a commercial one, I've found that my craft has driven me to explore in various mediums.  Meaning, doing graphic design does not eliminate the need to write well or understand marketing, and painting in oil does not mean that I won't have to paint digitally.  Photography has become the next necessity of trades to be added to my portfolio of mediums and thought it is useful and I've learned quite a bit, I have a long way to go.