When it comes to armed self-defense, a little knowledge can be a dangerous thing. For example, using a weapon-mounted light is an excellent idea – IF you know what you’re doing AND you’ve practiced under stress. If you don’t, a great many things can go badly wrong. Leaving a gun light on as you sweep a room or house tells the bad guy exactly where to aim his gun and/or mount a physical attack. A far better technique: switch the light on for a quick picture, then turn it off a fraction of a second later and move (while listening for target information). To do that, though, you have to have the right gun light and excellent control of the mechanism. And then there’s whole firing the gun thing . . .
At some point you may want to leave the light on and pull the trigger. Can you make that transition? Without delay or mistake? There’s only one way to know: try it. Preferably in a class shooting Simunitions or Man Marker Cartridges at a force-on-force pretend bad guy, in the dark.
Alternatively, forget the whole weapons-mounted light misegos. Carry a flashlight in your support hand and practice shooting single-handed (realizing that squeezing the light’s switch with one hand may cause you to pull the trigger with the other). Or, I dunno, call 911, turn the lights on, assume a defensive position and wait for an attack or the cavalry.
A lot of people love the idea of a weapon-mounted light. That’s why companies make them and NRA commentators comment on them. But there are an awful lot of variations on the theme; including dozens of different activations protocols. Unless you’ve thought it through and tested your gear during low-light firearms training, a weapon-mounted light could be a lot more trouble than it’s worth. Just sayin’ . . .