If you are a person inspired by ideas, you have probably encountered the concept of "fail fast". You probably also have read the Steve Jobs' commencement speech where he illustrated how a random calligraphy class that he attended in college influenced the ways computers were designed throughout the world.
I think both are true.
We do have to cut our losses when we realize the road we're on is not going to take us where we want to go. This is hard. To leave goals is to walk away from money spent and time invested. However, there are times in life when the wave of the future becomes obvious and denying it is pointless (think of the internet or the iPhone).
However, I believe that no sincere effort or pursuit that is intrinsically valid and worthwhile returns void. In my own life, people literally laugh when I tell them I studied Rhetoric in undergrad, but the classical Aristotelian fallacies I learned way back when have added value every day of my life and have helped me develop into a critical thinker.
What do you think?