I got varying reactions on my last post. Some thought the story about making coffee using an extremely detailed plan was funny.  For example Fabio Akita wrote:

"Planning is the death of any project" http://bit.ly/bFYkAW Just an entertainment story, but fun nonetheless

I'm certainly proud to produce something that is considered fun. Yet my little story actually has some serious background. Of course the simple task of making coffee doesn't justify elaborate project planning. But which task does? As we have seen, simple tasks don't.

So how about complex tasks? Tasks that depend on circumstances in many ways, like e.g. balancing a stick on a finger, or playing table tennis. It would surely simplify the task, if we knew exactly when to make which movement. But we can't plan this kind of thing, because the tiniest deviation from the intendend movement at some point in time will greatly change the required action some time later.

The coach teaching me project management had a great example of a project needing very accurate planning: When you build a nuclear reactor, the core will get encapsulated in a huge steel chamber. There are only very few cranes huge enough to move this thing. And they need a rail track to get to the building site, as well as a foundation for the crane to stand on. Rent of this crane is expensive as hell and you have to fix the dates years in advance. Everything that was needed for this crane and the needed structure, was planned with great care, to make sure everything was in place.

Few of us build nuclear reactors. For all others check these rules as a guide for the amount of planning justified:

• How plannable is it anyway? Don't try to plan the unplannable. Get it out of the way instead. This is what many agile approaches do, when they implement the most risky stuff first.
• Do you have fixed dependencies between tasks? A plan becomes more helpfull, when you have many dependencies between tasks, possible with long ramp up or preperation time. As with the crane: The task of moving the steel shell wasn't  very long, but the preperation had to start years ahead. Without a plan it gets easy to kill a deadline long before it comes into sight.
• What is the damage done, when you don't stick to the plan. In some projects, the only damage done is that somebody has to adjust all the plans. In that case, you might just as well scrap the plan.