Iterate!
I have been doing iterative product development for a few years now, and iterative management has got into my DNA and now that I see that there are several waterfall-like ways of management; for instance, a six-sigma plan, which is extremely detailed and elaborate, I wonder, how could people be so sure of themselves and their plans . Iterations allow you to correct your mistakes along the way and the mistakes are manageable, but if I create a 1 year implementation plan for 20 guys and then the plan bombs at the end of the plan execution...what a colossal fall! As much as possible, go with iterations in work and life . Because frankly, your 3-week plan is not going to hurt you as much as your 2-year plan, assuming of course that your plan bombs at the end. Now, one more thing! I clearly understand that great things take time to accomplish . For instance, you would probably need an year to bulk-up your muscles...so, the planning must be for an year, but if you go the iterative way, ...