A few years ago, we visited some friends in another town. Their congo didn't have enough publishers to effectively cover all their territory, so what they did was to knock once. If no one answered, they put a bible study (Would You Like to Know More about the Bible?) tract in the door and went on. They wouldn't write that house down to try again later. If someone did answer, they immediately tried to place the magazines and start a bible study. We covered a lot more houses that way, and the territory was turned in faster by not trying to go back to houses where no one was home the first time.