The “correctly” part is the hard part for a lot of people, I think. It’s easy to lazily dry fire, it’s hard to be honest with yourself when a rep was shit. I still struggle with the temptation of “well that was good enough” even if I know I didn’t have my sights or my grip was fucky or whatever.
But when done correctly, it really works. Back from 2011-2014 I was a sponsored shooter and I rarely dry fired because I had free ammo, and I got pretty decent, knocking on the door of USPSA Master. Since 2014 I’ve hardly shot because I have been really busy. So this year I got back on a regular dry fire program, coupled with a once a week range session. Working fundamentals 3-4 days a week in dry fire with a 200-250 round focused range session each week all of a sudden has me shooting 4.55 FAST drills again, and I’m all “shit wait when did that happen.”