Around the public land I hunt , there are lots of farms with barking dogs and crowing roosters . Them da'gum roosters never sleep it seems . I use them as a guage . I know where they are and how far away they are . When I hear that gobble I can then estimate how close to get . Knowing the lay of the land also helps .
And , like has already been brought up , the foliage will effect the carry of sound . Also which direction he is facing ,,,wind direction and strength ,,,on the ground or in a tree .
I have also made it a habit of looking right at any crow I hear just to see how far away it is ,,,another guage of distance.
I know there is a lot of hunters who work at getting as close to the roost as possible . Many I have read about willing admit they bump a lot of birds off the roost . Personally , I'd rather have him hit the ground unspooked , even if he walks away . At least then I can reposition and try something else to fool him . Bumped from the roost is generally a spooked bird and he may be hard to get interested in your calls . Just something to think about .