How Long Does First Hokage's SM last?

[Draphsin]

I'm going to take a wild guess & say a long ass time. Lol

 

[Sot6p]

Naruto has yet to reach his prime. The boy is at least 20 years away from it, actually. And now that he knows the secret of Kage Bunshin AND has Kurama as a partner, what could be his limit?
I don't know how long it'll last then, but it'll probably be more than 5 minutes.

 

[Xāvî1]

Actually. His Sage mode last for a very long time. Plus for how long has it been on? Since they made the four red suns barrier.
Naruto who is said to have mastered Toad sage mode, doesn't last long.
Now why can't naruto maintain his SM? He is only good for 2 spiral Elements...
Am confused

because naruto is not using fukaus and shima to collect the natural ennergy for him