Huh?
The desired effect is to stop the threat.
If you can stop the threat without firing a shot, you just saved yourself a sh!tload of lawyer money and legal headache.
Be prepared to? Damn right! Fire for effect? Only if the bad guy makes it necessary.
Unfired guns make criminals flee thousands of times a year. To think that you HAVE to shoot EVERY threat is foolish.
I never said anything about shooting every threat, nor did I say anything about displaying a gun to every threat, but if yo pull your firearm you should intend to fire it. It is not a threat. If he quits, turns and runs, drops to his knees or in someway shows me that he is no longer a threat GREAT! But he better do it quick as he has about 1.7 seconds if I am wearing a tucked in shirt and less if I don't.
If I am not in fear for my life then he will never fear for his.