Board Thread:Theories and Speculation/@comment-27082825-20150128192929/@comment-25632268-20150129102607

Iar Sensei wrote: Greatest Sin, I believe the cycle restarts about a year or so after both incarnations are dead

Yeah, think the same. I once tried to determine how much time passed between Kanabi Bridge mission and Naruto's birth and it seems to be something between one to three years (it would be easy to guess if we know Kakashi's age during Kakashi Gaiden, as Hatake was 14 at the day of Naruto's birth). And Madara died not long after "saving" Obito.