The notion that your adversary is untrained, or not training, is something that will get you killed. While you don’t have to presume skills you adversary doesn’t have, you should not underestimate him (or her, or them) either.
This news report highlights the lengths some of these guys will go in order to be prepared. A gang leader built a shooting range in his basement which the police only discovered when they executed a search warrant on the proeperty. As is, access to the range was hidden by a manhole (see video at link). This range looks to be a sophisticated set-up, and this individual and his cohorts are unencumbered by “Range Rules” and “Range Mindset” when they practice. On the street, they are also unencumbered with a morality to worry about where stray rounds end up (unlike you), but are training, and training means they are more likely to get hits. Notably, a study by Dr. Bill Lewinsky, entitled “Accuracy of the Naive Shooter” suggests that there is little difference in the shooting accuracy of novice versus skilled shooters at short distances. Yet skilled shooters, as the study demonstrates, also mitigate the advantage of distance which is where we train you to slow down, take your time, and get your hits. Lastly, remember regardless of the skill level of your attacker, he doesn’t need to necessarily be “good,” just “lucky.” Dead is dead, whether it was a skilled, accurately placed shot, or a “spray and pray.”
Train regularly.* Train safely. Train with continuous improvement in mind, and benchmarks so you know your skills, what you can and can’t do, the kinds of shots you can and can’t make.
Also train in a variety of conditions. Think your assailant will care that it’s 10 degrees outside with snow and ice on the ground? Nope. Think he’ll care that you are sitting in your driver’s seat with a seat belt on, having a hard time getting to your firearm? Nope. Have plans when you go to the range to not only hit some established bench marks for yourself, but also to try different situations (empty gun first) so you can see how easily and safely it is to get to your firearm, for example, when you are seated similarly to you driver’s seat, or you are wearing your heaving winter coat. If you can’t get access to your defensive tools, re-assess where you carry them or what you are wearing.
Don’t underestimate your adversary’s skill, strength, or will to get what they want from you. And don’t overestimate your own abilities.
*By “training,” I mean more than going to the range. Dry fire, dry fire, dry fire!