Some parents might not agree with me on this point, they might feel a strict lights-out and bedtime is important. I figure I'm strict with screen time and with snacks, so there should be one area where I do not place limits on my kids. I let them read as long as they want to, and I even provide them with a small LED lamp to read in bed. No need to waste batteries with flashlights under the blankets... They don't stay up all night, but sometimes they will fall asleep on the book. It's OK, drool can be wiped off.
Having good reading light is important, and I have posted two instructables on the subject, one made of mahogany, the other with a tin can. LED bulbs are perfect for kids reading lights, because they don't get burning hot and their light is directional and not too bright: it will light up the page, but not the room.