I agree with Bama above. A light that is too bright can be a detriment indoors with bounce back off walls and such. Generally speaking, 100 - 500 lumens is plenty for target identification. I have a WML that is quite a bit more (Olight PL-2 Valkyrie) on my night stand pistol but firing angles/distance for me in my house, using this particular pistol could be up to 25 yards across a large open room so bounce back isn’t an issue. For down a hallway a 100 lumens, like a TLR-6 is more than sufficient. A lot depends on your floor plan and likely angles and distances of fire.
As an example, from a review I did on the TLR-6 on my P365XL about a year ago whole my new house was under construction:
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Some beam shots I took tonight out at the property with the P365XL w/TLR-6.
I was standing to the right of a 25 foot wide space between houses. The black tarp in the distance is about 100 feet away, perhaps just a tad more. The end of the house is about 77 feet distance from where I was standing. This was about 9:15 tonight and it was very dark without the WML activated. Dark enough that you would not have seen someone towards the back of the house.
This is standing just in front of where my front doors are going to be. The back of the lanai is about 75+ feet away. Again, the black tarp beyond is a tad over 100 feet away. I would have easily seen someone clearly standing on the lanai. So that would be a 25 yard shot to the lanai and perhaps a 35 yard shot to the end of the backyard give or take a foot or so. In person it is clearer as this was taken on a cell phone. I would have easily been able to identify a man sized target in the backyard.
One of the hallways in the house. Distance to the back wall is about 33 feet give or take a foot.
For only being 100 lumens, I feel the TLR-6 is more than sufficient for most likely scenarios. I feel I'd have no issue identifying a target out to 35 yards. With the XL I know I would have no issue hitting a target at this distance. I've done so in matches with the shorter barreled P365 in dim light conditions. So while a brighter light would be nice and could have it's uses, I think the TLR-6 is a good light for it's size, run time and lumen output. Although I'm sure it could happen, it's hard to imagine a SD scenario where one would need to take a shot at a distance longer than this light is capable of reaching. It's also worth noting that I could easily and clearly see the night sights with the TLR-6 activated.
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This isn’t to sell you on a TLR-6 but rather show you what a 100 lumen light is capable of for comparison purposes. Keep in mind that you don’t get the full effect from a cell phone camera and it was even better/clearer in person.