This bag has plenty of room for the things you think you might need while away from home.  I use it for the things we have realized would be good to have at times now that the kids are out of diapers.  I have in it, first aid kit (2 day size), 2 backup diapers, 4 disposable ponchos, sanitizing hand wipes, ear plugs for those loud movies, 2 small sippy cups for when the restaurant doesn't have lids, mosquito spray, tissues, crayons, toilet seat covers, sun screen, and still have room for a concealed weapon.  I haven't put a firearm in the pocket, but it should support a midsize semi auto, like a G19, just fine. It hangs nice and isn't as hot as a backpack.  I have used th side pockets for water bottles a few times and they are a great place to put your sunglasses.  I use it to carry the things that make our life easier and safer.