Usually 40 yards for a turkey setup, but you may go less or further out depending on the gun and the way it patterns. Start at 40 and don't shoot out further than what it will put a dozen or so shot in the head/neck of a target.
As I sit and glass, which is common for hunters out west, I have sort of quickly discovered something I never learned when I was younger.
In my youth I had enthusiasm and spirit. In my middle to advancing years I have creaky knees, arthritis, and I tire more easily than I used to. Where I used to sit on the cold hard ground I now look for that soft spot to sooth my tired muscles. That leads me to my tip.
Carry your soft spot with you!
In my pack I carry an air filled, ultralight, camping pad....