Rules are part of the crunchy goodness in Office workflows. We'll delve more deeply into rules as we progress through this chapter (not that "crunchy goodness" doesn't tell you everything you need to know, but I do have a whole chapter to fill here), but think about it this waywithout rules as separately definable entities the following are true:
A workflow locks a business process in as a snapshot in time.
Business logic is tightly intertwined with processing logic.
Documenting and tracking business logic is made more difficult.
None of these are ideal.
With rules, however, we can extract some of that logic and define it separately. If that part of the logic ever needs to change, we can update the rule and leave the rest ...