David Brooks has a nice piece in The New York Times on two ways to live life. The first is from an essay Clayton Christensen wrote for the Harvard Business Review: 

Christensen advised the students to invest a lot of time when they are young in finding a clear purpose for their lives. “When I was a Rhodes scholar,” he recalls, “I was in a very demanding academic program, trying to cram an extra year’s worth of work into my time at Oxford. I decided to spend an hour every night reading, thinking, and praying about why God put me on this earth.

Essentially, Christensen proposes applying business planning techniques to life, developing strict plans and purposes. I think I tend to do this, often subconsciously, thought the older I get the more I realize the truths behind a summoned life:

This mode of thinking starts from an entirely different perspective. Life isn’t a project to be completed; it is an unknowable landscape to be explored. A 24-year-old can’t sit down and define the purpose of life in the manner of a school exercise because she is not yet deep enough into the landscape to know herself or her purpose. That young person — or any person — can’t see into the future to know what wars, loves, diseases and chances may loom. She may know concepts, like parenthood or old age, but she doesn’t really understand their meanings until she is engaged in them.

Like Brooks, I think a healthy balance of both of these are good. Plans are important, but being open to exploring outside those plans are equally fulfilling.