As others have stated, it really depends on the situation. Some places it is useless,...and maybe even counterproductive,...to try to locate birds,....and in other places it is an absolute must to use locator calls and try to locate gobblers on the roost. Personally, if I am hunting a significantly large area that I am not familiar with, I will use locator calls to actively try to find birds before I start hunting. I don't consider that to be just important in my hunting strategy,...I consider it to be essential.
On large tracts of public land, in particular,...and especially out here in the west where turkeys are sometimes widely scattered across vast areas,...it is crucial to first find the birds before you start hunting them. Spending your first morning doing nothing but covering as much country as possible and using a good locator call,...especially in those first couple of hours at first light,...will often mean the difference between success and failure over the course of your hunt.
But even on small tracts where you can hear from one end to the other from one location, it is sometimes advisable to make a bird spit out a gobble earlier than he might on his own, so that you can approach the roost under the cover of darkness.