SD Training-train to reality.
CAVEAT: Below is simply my observations and opinions. I am not an instructor, but I did survive 6 years of combat during my 30 year Marine Corps career. Just read and consider. Then adopt or disregard as it fits your mode of defense. This is not set forth any sort of definitive gospel!
Training can help, but if it is to become "second nature" it must simulate the actual conditions under which you are likely to be attacked. An LEO needs to train at all ranges because his uniform and aggressive posture may draw early fire at a distance. In my case my threat is a rush from 21 feet or less in a dark parking lot or at an ATM. The training for these two scenarios are totally 180 degrees out. I train for in close (<21 ft ) pointed, rapid fire (empty gun at COM)because this is most likely what I will need. I will be in a mugging situation, not a gunfight.
I attended GUNSITE in the old days when Jeff Cooper was still honcho and the training I received there was great for gun fighting and combat. However, it is just about useless for my mugging scenario. It is the same reason I went from a semi-auto in an OWB holster to a revolver in the pocket for carry. I won't have time for more than five shots (I will be lucky to get off two or three!) and definitely no time to clear a Failure to Feed or a misfire.
Definitely train, but train to your needs, not to whatever is currently "cool" at the schools. Training to all scenarios is a lesson in rhetoric. There is as much difference between distant (>15 Yards) aimed handgun fighting and in your face (<21 ft) point or even hip shooting as there is between a sniper and busting down the door of a house and rushing the room types of shooting. One of them will become the second nature reaction you need. Practicing both means neither one will set as a reaction but will remain a mental option. At 10 feet you have no time for mental options.
SA helps but you eventually need to get to your car and you can't always park under the lights. I always walk to my car with my hands in my pocket (see mode of carry above).
Again, I train to a sudden, short burst of action in close. Your scenario may be totally different, in which case train to the predominate scenario.