[Endurance][1] conveys the concept you are describing:

• lasting quality; duration.

[enduring][2] :

• Lasting; continuing; durable: a novel of enduring interest.

( from TFD) [1]: http://www.thefreedictionary.com/Endurance [2]: http://www.thefreedictionary.com/Enduring

Endurance conveys the concept you are describing:

• lasting quality; duration.

enduring :

• Lasting; continuing; durable: a novel of enduring interest.

( from TFD)