This is predicated on non-emergency situations. "On the third approach the pilot lost control of the aircraft and all aboard were killed." I first noticed a pattern of deadly third approaches during my instrument training when I read all the accident reports I could. My primary rule is to NEVER make a 3rd approach. If you are 121/135 you almost never divert, after all the weather must be at or above min vis for you to begin the approach. But it does happen and part 91 it is even more likely as you can go "take a look." This is how I make the analysis. On the missed approach I ask myself why I missed. There are three possible reasons for the missed and only one of them permits another attempt. First, I screwed up. Second, the weather was below what was reported or expected if no reporting. Third, something critical in the airplane broke. I only try again if I screwed up. I give myself a chance to make another attempt to get it right. After the second attempt I'm off to an easier approach. If I missed twice then I am too tired or too rusty to try a third time (see first sentence above). If the weather is too low it is too low and why bother with another approach and more fuel gone when the outcome will be the same. If it is something critical broken in the airplane then I get myself to an easier to complete approach. Why shoot an NDB when an ILS is less than 50 miles away? What are your rules?