There exists a school of thought in the gun community that you should always train like you intend to fight. While this is certainly solid advice from a tactical standpoint when it comes to muscle memory and accurate shooting, there is always some yahoo on the range who takes that mantra a little too far.
Interchangeable combat and tactical gear has made huge strides over the past 17 years. Perhaps it’s due to the nation being at war for the past 17 years and what better test to evaluate combat gear’s effectiveness than, well, combat. Lessons from the battlefield taught infantry types the need to customize their gear for max effectiveness rather than embrace the standard operating procedures handed down by some butter bar 2nd Lieutenant. In the end, if you are going to win the fight of your life you need to know your gear as if it were a part of your own body. You should train with your gear like you intend to fight so that when the snap and crack of a bullet flying overhead rings out you are not struggling to find your extra magazines or ammo. Want to win the fight of and for your life when it happens? Customize your gear for the fight ahead.
There are times and situations where a flashlight just doesn't cut it. Every time you're using a flashlight, you're multitasking. That means you're using your free hand to do something else and you'd rather have both hands freed up to focus on the task at hand. It could be the difference between life and death, on whether or not you can protect yourself, on finding your way or staying stuck, or just a matter of convenience. There are situations where you just need both hands to deal with a perp, set up your gear, or manage the everyday tasks made more difficult under the cover of darkness, even if it's just fixing a flat.