I would love to be able to calculate start dates and due dates based on another date field. We have a compliance task that needs to be done every two years based on the day that it was last completed. I'd like to be able to input "date last completed" and have the next due date and start date calculate accordingly.
I can see other use cases for this as well as we have client due dates (a hard date that something needs to be delivered to a client) and an internal due date (the date that our team is shooting for in order to complete the task in enough time). I want the client due date to drive the the tasks due date and start date.
I am certain there are likely other applications of this, but these are the two that come to mind immediately.