Great question...

Usually I have this battle with myself over move or not move. But ultimately, I let the bird determine that. If Ive got a bird working and he is making progress, Ill stay no matter what. If he goes silent on me, Ill wait a long time and reduce my calling to a minimum. Experience tells me that silence comes from a number of factors, not limited to 1) he found a hen, 2) He is moving but just quiet, 3) something spooked him.

Ive had so many birds come in quiet that the time i go quiet waiting has often paid off with birds I wan' t even aware of.

But...no doubt, I move when the urge gets to great and have stood up only to spook a gobbler watching me...