When I can. It is difficult to since our dept. range has day hours, as do most of the shooting schools do that I have attended. Our nighttime qual course does not even involve a flashlight. A pain in the rear, since at night I always have one.
Did a fair amount of low light sniper training in the sniper schools I attended. The basic course involved using headlights near the target for a three second exposure. The target was blacked out, lights on, lights off. The advanced had the light source at the yard line that we were at, either 200 or 300 yards. At that distance you can see the outline of the target and nothing else, unless you have NVGs. Low light is where a varible power scope comes in real handy. Power it down and you grab more light, not alot, but enough to help out. I saw guys with Mk IVs losing their cross hairs in lower light. Another trick we learned is to take a small light stick, I think that they are called peanuts, and tape it to the bottom of the scope, just inside of the front objective. Gotta be creative with the tape or all you will see is a glow.
Would OJT count? Plenty of times where I have searched dark areas with weapon and flashlight.