A climber on an expedition to Mount Everest doesn't just step out of his tent one morning in the base camp, pick up his rucksack, and head for the mountain. He starts out by carefully planning the stages of his climb, splitting the total task into smaller subtasks. This allows him to focus on task at hand and give his full concentration to climbing through the dangerous Khumbu Icefall at 18,000 feet, without worrying about the Hillary Step at 28,840 feet just below the summit.

While enterprise ADF development might lack the glory (and danger) of climbing Mount Everest, the idea of concentrating on the one task at hand still applies. Especially while you're new to ADF development, concentrate on one task to avoid being overwhelmed by the full complexity of the whole application. This is another reason to build your enterprise application as a number of separate subsystems.