I just grabbed a very affordable and quite small sling bag from a very popular shopping site. I know there are some very rugged and reliable bags out there and thought that if I can get used to carrying this affordable bag then I can justify (to the wife) that I need something more. My thoughts were to use it for something I can grab and toss in the car every day. The dimensions according to the site are: 11" x 7.8" x 3.9" (L x H x Thickness) As it is fairly small, I'm really trying to maximize what I can carry in this little guy. I'm reworking one of my first aid kits to carry the essentials and I'll have a small pad and pen in there. The only other thing I can think of is a small burp cloth for when our almost 5 month old girl is out with me. We carry a diaper bag as well but those little cloths are invaluable. What else should I be looking to carry every day? Please point me in the direction of something that will come in handy! Please keep in mind that on my person I carry a couple folders, sometimes a fixed, handgun, spare mag, and flashlight. Also, I already have a bag I use for hiking that has the essentials in it so I'm covered there...I think.