A document has a lifespan of 60 days beginning when it is uploaded. At any time during those 60 days আপনি can "reset" the life back to 60 days simply দ্বারা making a change and saving it. Regardless of whether that change is adding 1,000 words অথবা deleting a single period, it will restart the clock.
This 60-day life only applies to documents in the document manager. Actual published stories are not subject to a time-limited life.