Out of all the EDC gear I carry, the flashlight is the one I use most often. To look at things in the dark, to identify potential threats, to find something that fell on the floor on a recent airplane trip, and even to look inside a wall to find the screw to line up with a mounting bracket. – which was in the bright Az sun at like 3pm and when it was 118 degrees, never thought I would need a flashlight in those conditions! These are some of the reasons you always see me talking about a EDC light, and here is a video where I go into more depth on the whys and hows
Streamlight ProTac 1L-1AA Still the #1 flashlight I recommend to everyone. Perfect balance between size and output, dual fuel so can use AA battery if needed, big enough where you can do some damage with the light if that is all you have on you (like me when I travel). Price, warranty, tailcap activation= everyone should own a few of these- I give them away all the time to friends and loved ones. AMAZON LINK
Surefire Stiletto Pro If you want a brighter light that is also rechargeable, then this is the best edc pocket light. 1000 lumens, rechargeable, dual buttons, and sits even better in the pocket. Talking to Surefire though, these may be TOO powerful. I have already had to send mine back 2x to get replaced/fixed after the LED burned out. So the Streamlight is still the one I recommend for most. AMAZON LINK