Many folks leave their defensive practice to chance and actually spend very little time doing anything other than target shooting. Those folks show up a the range and send some rounds down range and hope that there will be some benefit. There is a better way and, oddly enough, it can also be practiced by the toss of a coin.
I've been saying for a long time that all such "standards" are made up and ultimately Subjective.... and therefore, not important... certainly not as important as so many people make them out to be.