There are a few items that every pilot should consider mandatory for every flight, items that are not required by the FAR’s but still prudent so as to not be overlooked. One of the simplest is the flashlight. I got his one from my mechanic (forgive the quick shout-out) at First Line Aero.
I cannot tell you how many times a simple flashlight has saved my bacon on flights. Yes, most of them have been at night, but the small flashlight can be handy during dark overcast days and when you need to get something under the seat or troubleshoot a situation under the dash. A good powerful light can illuminate the exterior of the airplane to inspect for ice build-up. I keep two on board at all times.
Another good tip…use flashlights that are powered by “AA” batteries. Other items in the airplane are powered by “AA” batteries (headset, radio, etc.) and you will be more apt to have a fresh replacement battery if there are not multiple types needed for various items.