Paul Simon has a song called ‘One Trick Pony’ with a bit in it that goes like this:
One trick is all that horse can do
he does one trick only It’s the principal source of his revenue
In the world of programming being a one-trick-pony is not an option. What it means is that when that one technology that you’re currently married to becomes obsolete you’ll be instantaneously out of a job or out of customers. Sure it pays off to be an expert in ‘x’ whilst ‘x’ is in fashion. But that is a limited time window.
Do yourself a favor and recognize that the tech world is moving much faster than it used to and that having only one blade in your arsenal is a surefire way to eventual obsolesence. It also helps to make you appreciate other points of view in debates about languages and their relative merits (not as important as you might think) and will make you a much better programmer. The single biggest boost to your programming career will come when you master a second technology as far removed as the one that you are currently using as you can stomach.
Lifetime careers no longer exist. I knew a bunch of people that were charging $200 per hour to do HTML in the early 90’s. Frontpage ate their lunch. Don’t become a dinosaur waiting for the impact of the comet in your safe little life be adaptive, and start adapting before you really have to.
Oh, and Happy 2015!