That's the light sensor doing its job. In AUTO mode the light only activates when the room is dim enough AND motion is detected, so it stays off in daylight to save battery. Test it in a dark room or closet, or slide the switch to ON for a constant light regardless of brightness.

No drilling. The puck itself is magnetic and snaps directly onto steel surfaces (a fridge, locker or metal door). For wood, tile, painted drywall or plastic, press the included adhesive metal plate onto a clean, dry, smooth spot and the light holds to it. It is not recommended on wallpaper, freshly painted or heavily textured surfaces, and the adhesive plate is intended for a fixed position while the light pops on and off.

Warm Glow (yellow) is calm and easy on sleepy eyes, so most people use it in bedrooms and on the route to the bathroom. Soft White is brighter and clearer, which works well in hallways, on stairs, and inside closets and kitchen cabinets where you need to see labels and details. Both are the same light with a different LED color.

There's no fixed number — runtime depends on how often you pass by and whether you use ON or AUTO. AUTO mode is the most efficient because the light is off until needed. When the glow becomes noticeably dim, simply lift the puck off the magnet and charge it with the USB cable, then snap it back.

Yes, the ON position keeps it steadily lit until you switch it off (this drains the battery faster than AUTO). The low-power LED stays cool and is designed for indoor, dry use. Keep it away from water, heat sources and very young children; don't mount it directly above a pillow, and charge it with a normal 5 V USB port rather than a damaged cable.