Being flexible in your skills and talents is a vital key towards being employable long term. I have heard it said that a person should complete an undergraduate degree in one specific area and then in post-graduate study work on skills and understandings that will make you flexible.
So why flexibility?
Flexibility keeps you supple. Being supple means that you can bend with the strains and stresses of life as well as at work.
Flexibility makes you strong. As your skills develop so does your strength. You become more able to withstand the rigours of life and business.
Flexibility gives you speed. Speed is the ability to adapt and change as quick as you can when you are required to.
Flexibility will stand you in good stead as far as your career is concerned. If you are supple, have speed and are strong then you will go well and go long.