The National Do Not Call Registry registration is valid indefinitely as long as the phone number remains active and registered to the consumer. Once a number is registered, it will remain on the list until the individual removes it or the number becomes inactive, such as when a person changes their phone number. It is important to note that if a number is disconnected and a new number is obtained, that new number will need to be registered separately on the National Do Not Call Registry. Consumers should also be aware that registrations do not expire, but telemarketers are required to update their lists regularly. For more specific information or updates, it is advisable to look on the current web page for the National Do Not Call Registry.