First of all, I have things sufficiently organized, and I'm good enough about putting things back in their places, that I can usually find most of my stuff in the dark. I can do a lot of things by touch. When I need light, I turn one on long enough to do whatever it is I need the light for, then I turn it off.
I've also discovered there is often enough ambient light coming through the windows. Distant lights, someone's fire, moonlight, etc.
But my main source of don't-turn-on-the-lights light comes from small LED indicators on my charge controller and battery monitor. That's really quite a bit of light when one's irises are fully dilated.
Oh look, I can see the toilet paper and hand sanitizer
Consider that artificial light is no simple thing for a lot of people in the world, and that it was a rarity for most of human history. But as with most modern conveniences, we've come to consider nighttime light as a necessity. It's getting dark, turn on the lights. We even turn on lights in the daytime.
Maybe it's a remnant of the primitive fear of things that go bump, or that growl, in the night. Light claims our space, establishes a perimeter, banishes the beasties. Yes, light extends the day, but it also extends us. Our world becomes much smaller when wrapped in darkness. It's just me, and the things I can touch.
We tend to think not having enough light is bad for our eyes. But maybe not having enough darkness is what's really bad—for our eyes and for our minds. Maybe we become less of a person when we can't function in the dark. Or maybe I just spend too much time in the dark, thinking weird things.