When sending reminders for overdue tasks, I've noticed that the "Number of times to repeat" property will not accept a workflow variable. This is the case for both the "Assign a Task" and "Start a Task Process" actions.
This is far from an "issue" but definitely an inconsistency with the product. I've run into a case with a customer, where being able to drive this value from a variable could have saved a good bit of design time.
Thanks!
Patrick