It's important to note that DL starts the 1 year expiration clock from the time the ticket was purchased, NOT from the date of the flight. NW started the clock from the date of the flight.

Can someone confirm that w/ DL you have to call ahead of time for the first leg. I've never experienced that with any airline. My experience has been that if you no-show for the first leg then the entire ticket is canceled and you end up with a credit (for non-refundable), for any legs past the first leg THEN you must call and then the entire rest of the ticket is canceled and you end up with a credit for the remaining value.