QueueDescription.DefaultMessageTimeToLive Property
Gets or sets the default message time to live value. This is the duration after which the message expires, starting from when the message is sent to the Service Bus. This is the default value used when TimeToLive is not set on a message itself.
Messages older than their TimeToLive value will expire and no longer be retained in the message store. Subscribers will be unable to receive expired messages.
Namespace: Microsoft.ServiceBus.Messaging
Assembly: Microsoft.ServiceBus (in Microsoft.ServiceBus.dll)
If you set the EnableDeadLetteringOnMessageExpiration property, then any message that is not received before its expiration will be moved to the dead-letter queue.