My occupation requires that I go to a rather "unfriendly" part of Memphis Tn on weekday nights. Because of this I have aquired a couple of peices of EDC gear and have developed what I think are good habits in regard to deploying them. The most often used peice of gear is my SureFire G2 Nitrolon weaponlight. I have fashioned a lanyard for it that I keep looped around my neck during the hours of darkness or when I think I might need it handy.
I practice frequently with this light. With my left hand I reach for the light and then place my fist, clenching the light, along my jawline while I draw my carry weapon with my right hand. With the light thus deployed, anywhere my head turns I have light. I have on several occasions had to use this technique(sans actually drawing my weapon) to discourage people from approaching me while I am about my business in Memphis. The 65 lumens prodiced by the G2 consistantly deters them from coming any closer and it ruins their night vision. Even if it is just a momentary distraction, it is enough for me to take the initiative if the situation warrants it.
A couple of nights ago (1 a.m.)I existed my shop to go retrieve a couple of cases of ammo from the bed of my truck. I was startled by a man that was approaching me out of the darkness. I instantly blistered his retinas with 65 lumens of light and put my hand on my pistol. He was obviously intoxicated, but not to the point that he wasn't a threat. I kept the light on his eyes until I could back away from him enough to get out of the danger zone. He did not advance on me, nor did I speak to him. To have spoken would have encouraged him to remain longer. If you have even dealt with a persistant begger, then you know what I mean. I concluded that he meant no harm, but wanted to bum money from me. He eventually got the message and left on his own. I watched him disappear into the darkness.
The point to this story is that those of use that carry weapons daily for protection should consider carrying other gear as well. If you only have one tool for every occasion, you are limited in your ability to respond. If all that I had had was a weapon, I could not have handled the situtation as peaceably as I did. I also would not have been able to turn it to my advantage as easily.
A weapon light is also useful during daylight hours. It only takes a milisecond to gain the upper hand in a confrontation and even in daylight, 65 lumens is enough to make a person turn their head or blink and eye. If you are practiced, that is enough.
ETA: I didn't realize that I was in the survival forum when I posted this. My apologies.