When i can get a one way signal its deep but reads good i usually dig because it might be a coin or object on edge,a lot of factors play into the decision to dig.The area you are hunting in, the ground minerals the size coil a lot of factors that come together in your head as you are hunting and catch a signal .I believe buried in your subconscious that from hunting so long and recovering and disappointment's sum of the results are buried there and are called on when making that decision.This is why sometime you will pass over a signal and it will register a solid junk but yet you have something that tells you that something isn't quit correct and you dig found many good objects this way,that the machine said pass on by.Like a high school ring on way back to car in hurry machine running go over signal and hear it and look at the machine and says penny keep moving didn't want to dig a penny went a few feet and something inside me says that didn't sound correct go back and dig big high school ring about 20 years old only down 3 or 4 inches.I believe a lot of dig or don't dig is from past experience and with help of the machine we make a decision.Maybe this sounds a little far reaching.Hope this helps.But on the other hand their is the dig everything theory,but in some areas i hunt i would be crawling on the ground hunting and digging because of all the signal and trash.Good luck and good hunting.Wow now my head hurts .But what you learn over the years digging and not digging all come together some call experience some call luck.