There are a lot of BPM-related seminars and events about improving business processes and putting workflows to practice, etc. Many of the case studies in these seminars are of the "externally-initiated" category. This is probably because interactions with and responses to customers (stuff like issuing quotes and answering inquiries) are directly connected to profit, so they are of interest to companies.
If you want to get a concrete grasp of the time it takes to execute a certain task or set of tasks, it's often convenient to separate them as individual process models. That way it's easier to monitor that portion. And if there are any tasks that precede that portion, just use a Message Throwing Intermediate Event to link them.
