Defensive coordinators probably haven't walked with a sense of comfort around the New Orleans Saints practice facility in quite a while.
The longest shelf life for a defensive coordinator with the Saints under Sean Payton's watch has spanned three seasons. Gary Gibbs and Gregg Williams each lasted that long. Rob Ryan didn't finish off his third season. Steve Spagnuolo made it one year and never even coach with Payton thanks to the bounty scandal sanctions.
Dennis Allen is entering his third season as the Saints' defensive guru. There's no reason to believe a fourth season would be a stunner.