I'm fortunate that I've been able to attend a lot of high quality training, from a lot of different schools and instructors. One such course a few years ago was a Two Day Combative Pistol Course. On day one, after the lecture, we hit the range hard, performing drill after drill. On day two, we arrived in the classroom and sat down, coffee in hand, ready to receive the opening lecture. Instead, the instructor walked in and said, "If you walk out into the parking lot and someone offers to kill you right now, they are not going to give you a chance to warm up first, so let's go out and run some timed drills NOW!" That lesson stuck with me, and I still utilize it to this day.
Many shooters trying to improve their abilities will perform some sort of warm-up, prior to running timed drills to test, and improve their skills. My personal preference is something that is often referred to as 'cold starts'. First, pick a drill that is geared towards improving your ability to use your pistol quickly and efficiently in a defensive context. There are many such drills....such as the Bill Drill, the 5x5 Drill, etc. My three personal favorite drills are the Mozambique Drill, the 6 Shot Shoot-Reload-Shoot Drill, and the 11 Shot Concealment Pistol Proficiency Drill. These three drills, plus more, are found in the book 'The Little Black Book of Pistol Skills' (available at Openrange Sports).
Once you've selected a drill, the goal is to be able to walk into the range, and without warm-up, perform the drill to a level of 100% accuracy (no misses), within a given time frame. Once you've achieved that, then of course run the drill several more times, pushing the envelope......you are always seeking constant improvement....and always seeking to improve that cold start. The goal is not only to improve your physical skills, but also to increase your confidence. An additional training tip is to always train for this with your everyday carry gun, your everyday carry holster, in your everyday clothing.
In today's environment, violent encounters happen at the local grocery store, at Walmart, at shopping malls, and even at church. You may be called on to defend your life, and that of your family 'at the drop of a hat'. Knowing that you have the ability to perform to a high level on demand is vital.