Stand length depends on where I am and the hunting pressure. Some places I stay on stand 30 minutes or longer, but in general I only call for 15 to 20 minutes.
I call, then scan the area, then call again. I'm a busier caller than most with maybe a minute in between series. After my last call I wait at least a couple of minutes, then bino the area before leaving. I've had a few stands where that helped me coax in a dog that otherwise would have seen me leave from a distance.
I had a stand last week where a dog showed up over five minutes after I finished calling and was retrieving my decoy. Not much you can do to prevent that. Most coyotes show up for me between the five and twelve minute mark.
Nate
