For me flashlights are used outside about 80-85% of the time.
Headlights are a different story. I use them probably at least 60% of time inside which would leave 40% outside.
Lanterns are almost exclusively used inside. More than 90-95% of the time.
I almost never use the lantern and when I do it’s outdoors. A ceiling bounced light is much nicer than a lantern indoors.
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In my case that changes over time. My first flashlight was 100% outdoor because I haven’t thought of using it indoor. Then it was a mix but mostly outdoor.
Now I’m using flashlights 70% indoor simply because I spend indoor much more time than I used to and because my way of spending time outdoor has shifted as well to one that rarely requires me to use a flashlight.
I actually don’t EDC a flashlight nowadays though sometimes I miss having one.
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It depends. Small lights (AAA and AA) get used mostly indoors. Larger lights like dedicated throwers and lumen monsters with three or four cells, mostly outdoors.
I have several lanterns. So far I have only used them indoors. I find hanging them above eye level provides good area illumination. Something like the LT1 has hours of runtime on levels that allow me to see well enough for navigating a room. I got my lanterns for indoor use during a power outage. The thing is, with a dozen battery powered lanterns and 8 kerosene lanterns, I have had to use them about 4 times over the 10 years that I have been collecting them. I guess if I did more camping, the balance of indoor versus outdoor use would be different. 
Ceiling bounce works well… except I have a hard time placing the flashlights so that I don’t end up looking at them and completely screwing my night vision. Again, to be effective, I think the lights would need to be tail standing above eye level. Bottom line, when I have had to use lights like this (other than quick tests), it has been inside the house. It is kind of hard to use ceiling bounce… with no ceiling to bounce off of. 
Does your garage count as indoors? What if it’s not insulated and all the doors are open? Thats basically outside right? Feels like outside. If so then mostly outside. If not then mostly inside.
Interesting question, I think for me it varies a lot. I am almost as prone to use a flashlight in broad daylight as in the dark. There always seems to be a crook or crevice that has gobbled up something I need so I grab my DBC04 off my belt and click it up to the desired brightness … seems like I usually know about what level will be needed and just unconsciously take it there out of the gate.
Otherwise I grab a light that fits a need, whether inside or outside. Headlamps too, might use one in the daytime to give me a better look at the knife I’m grinding or the part I’m turning.
The Texas Poker has been around my neck for a decade, but seldom am I otherwise without a light so it doesn’t get used often.
Of course, most of my lights get used for something once in a while if nothing other than a few minute play to remind me what they do. 
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Mostly indoors lately, but I hope to spend more time outside again.
… and for indoor use, small lights are more than sufficient. So my bigger lights barely ever get touched.
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So sad for the bigger lights… 
Probably indoors more so than outdoors. Only because of the low light conditions at work. As I age it’s getting harder to see the small details I need to see. Even with cheaters on, that extra bit of light helps tremendously. 14500 or smaller 18650 lights serve me well. I only usually need a few hundred lumens.
Got that copper Acebeam Pokelit with the 519A in it. Did the dedoming on it. Phenomenal difference. Been carrying that a lot lately.
I’ve yet to dedome a 519A, slice it?
Yes, usually inside or outside.
Just push it off slowly from a corner with a little stick (e.g. decapitated Q-tip). Less dangerous that way.
It’s even more easy when the LEDs are slightly warm/hot:
Fairly even split between the two. According to my partner I use my lights more unnecessarily inside 
- usually inside for stuff like when going round the house before going to bed, some rooms that don’t have very good lighting but an SBT90.2 aimed at the ceiling solves that problem, nice colour lights for mood lighting, and just in general I often play with my lights while thinking, especially when working. Outside more practical uses overall.
I think it’s pretty evenly split for me. The lighting in my apartment is very spotty leading to more flashlight use. Heck, even my old stove has no internal light or window so I open it up and peer in with a flashlight at times.
I also take night walks with my lights on a regular basis.
I use flashlights and headlights outdoors almost all of the time.
I will use a lantern indoors the next time the power goes out.
(Ever since I acquired five lanterns for the entire family, the power hasn’t gone out.) 
Thanks Valynor and quahog, appreciate the tips.
Flashlights: 90% outdoors
Headlamps: 50/50 depending on the task
Lantern: 100% indoors
Mostly outside. More likely to find darkness outside I think.
I use my EDC fairly infrequently at home indoors, for the usual stuff - finding things, dark cabinets, headlamps for reading at night without disturbing others, and for working on things that benefit from having more light on it. At certain times I use it a lot indoors while working.
I generally use the light switches in the house instead of ceiling bouncing. Wierd I know.
There’s enough ambient light where I live that I don’t need to worry much about using a flashlight on moonlight mode to go to the bathroom or something, night vision is enough. Perhaps as I age that will change.
In terms of time spent with the light on, all that indoor use is easily overtaken by a couple hour night walk. I like to do urban exploring, and frequently go on long night walks/hikes and that’s the majority of my usage.
What’s interesting to me are the times where the light really comes in handy, even if it’s only used for a short time. Finding something small that’s hard to see maybe only took a few seconds of flashlight use, but would have taken ages without it, if it’s found at all.
I don’t really use lanterns. I have a couple diffusers and lights that work well as lanterns with them, but I barely use them. Other than while camping/outdoors, typically ceiling bouncing is enough for me instead of a lantern. I don’t like how bright the diffuser is to look at.
It is true, I use my lights mostly inside or outside.
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