For want of a nail,.....

 We all know it when we suffer serious misfortune, which we tend to attribute  to bad luck.  Many of us would say our  bad luck is more prevalent than our good luck.  However, because it is impossible to prove a negative, most of us, unless we win a million in the lottery, do not count among our portions of good luck the times that misfortune is averted, which can be a stroke of extraordinarily good luck:
   "He was leaving the rental house, home to a number of college students, when he noticed that the battery compartment to the only smoke detector was dangling open, empty of  batteries.  He dropped some money on the table, to buy new batteries, he told them, to replace those which had been appropriated for other use. He was ready to drive home, after a long day, when, so uncharacteristic of  him at the time, he had a sudden thought, or instinct, that none of the inhabitants would be likely to take the time to go buy batteries, so he took a trip into town, bought the batteries, returned to the house and installed them in the smoke detector.  Three days later, in the predawn hours, the smoke alarm activated, waking all seven residents of the house in time for them to escape what would have been almost certain disaster."
   The bad luck was monumental at the time--the fear, loss, relocations--financial and emotional issues that consumed precious time and assets.  But all is tempered by the passing of time, and what once was devastating is now only a dimming memory confined to the category of bad luck.  What turned out to have been immensely good luck was the placement of a few batteries, just in case.  By the time we live to ripe old ages, there are probably thousands and thousands of times that the good has triumphed over the bad.  We all remember the time we stubbed our toe, really bad, on that stand in the living room, but what about the millions of times we passed by that stand without injury?