I want more information on the usage of transaction IW36. How do you use it?

We use IW36, create sub-order, in the following instances:
- When there is a significant change of the scope of a work order. This allows the newly identified work to be fully planned, approved and scheduled before proceeding, whilst maintaining a link with the original order.
- For larger jobs/projects where a number supervisors may be responsible for aspects of the job.

Note: The superior order cannot be technically completed until all its sub-orders have been technically completed. For this reason we do not create sub-orders for orders created from a maintenance plan; it complicates the scheduling of the next call of the maintenance plan which is normally based on the technical completion date.

Eugene,

I suggest you also look at the SAP Help documentation for Order Hierarchy. it gives a good description of the intended use of Sub-Orders.

SAP Help