I understand the HOW and WHAT, but i have trouble with WHY, and WHEN?

Ive been reading up on WF, and I understand what it does and how to do it. But I am having trouble with is why I should use it, and when I should use it. I mean, if I have a process that I would like to write a file to a database, is that a good scenario I know it may all be subjective, but what is a good example of a scenario where it would be better to use WF rather than write my own routine

You want to use workflow for long running or complicated business processes where there is a lot of user interaction from the business community. Workflows serve as the glue between the software and the business users. Just imagine when you try to convey logic to a business guy, let¡¯s say a VP. He knows nothing about software but most people understand flowcharts. Now when you lay out the flow chart for the VP he is going to understand the full decision making process for that flowchart. The who, what and why are way more apparent when you have a visual.

Now let¡¯s say that VP defines all these parameters for the workflow and you get the workflow up and running. First thing this workflow gives you is tracking of the process. The tracking service will be extremely valuable to a business because you can report on when the states transition, who approved what, and overall efficiencies for that process. Also when you have a long running process that may potentially span for weeks or even years the workflow can serialize itself automatically using the persistence service. The state and everything about the workflow goes to sleep for another time. As a developer you don't have to save all that data yourself.

I could point out many more advantages and situations where you would want to use a workflow but I'll keep this brief. One more thing I have to point out is the business rules engine. If you have enough foresight and build your business rules intelligently when the business user inevitably changes his or her mind you can go in and modify those parameters controlling the rules at runtime without having to redeploy. You can also build an interface for users to modify the workflow itself and publish the workflow dynamically themselves. (Caution this may be a gift of fire)