This was brought home to me recently as an interesting phenomena concerning my photography "specialization". As I really like landscape style work (natural and urban) I thought it best to work towards this as my specialization - so many say to be successful you must specialize in a certain type of photography - but after a short while an odd thing occurred; I stopped taking photos. And when I did grab my camera to take any photos, it was not anything landscape themed. Instead it was to record our newest furry addition to our household - a young male rat terrier dog called Jax.
Other than puppy pics, the only other photos I have taken lately have been some headshots and portraits to practice techniques I've been learning from watching video classes on CreativeLive. And I can highly recommend the courses on their site.
Above is one of my (new) lighting practice sessions consisting of a softbox to Lisa's right, just above eye level; a reflector to her left at eye level and approx. 45° to fill the shadows; a second speedlight behind her to illuminate the background.
With all these things going on, I made the decision to drop my specialization attempts for now and "reclassify" as a generalist photographer and just shoot what appeals to me whenever I pick up my camera. Who knows, I might get really good at people photography and head that way, or I may end up shooting something completely different. At this time I couldn't really say, so until that day comes I'm just going to stay flexible.