I did this. It was worth the effort because it showed me what activities are a waste of my time. Jim Collins wrote about this subject for USA Today back in 2003:

Each time the New Year rolls around and I sit down to do my annual resolutions, I reflect back to a lesson taught me by a remarkable teacher. In my mid-20s, I took a course on creativity and innovation from Rochelle Myers and Michael Ray at the Stanford Graduate School of Business, and I kept in touch with them after I graduated.

One day, Rochelle pointed to my ferocious work pace and said, “I notice, Jim, that you are a rather undisciplined person.”

I was stunned and confused. After all, I was the type of person who carefully laid out my BHAGs (big hairy audacious goals), top three objectives and priority activities at the start of each New Year. I prided myself on the ability to work relentlessly toward those objectives, applying the energy I’d inherited from my prairie- stock grandmother.

“Your genetic energy level enables your lack of discipline,” Rochelle continued. “Instead of leading a disciplined life, you lead a busy life.”

She then gave me what I came to call the 20-10 assignment. It goes like this: Suppose you woke up tomorrow and received two phone calls. The first phone call tells you that you have inherited $20 million, no strings attached. The second tells you that you have an incurable and terminal disease, and you have no more than 10 years to live. What would you do differently, and, in particular, what would you stop doing?

That assignment became a turning point in my life, and the “stop doing” list became an enduring cornerstone of my annual New Year resolutions — a mechanism for disciplined thought about how to allocate the most precious of all resources: time.

Full Story: Best New Year’s Resolution? A ‘Stop Doing’ List