I just got a Guard three trumpet case (even though I have one trumpet). I am working on having the following in it: Mutes (may put them in a mute bag then the bag in the case) Lyre Folio Cleaning/care supplies Small but powerful flashlight A few small key chain/pen lights Mouthpiece (in it's own bag) Pens Pencils Paper Eraser Some basic medical supplies such as bandages, Advil, Neosporin, etc Trumpet stand Duct tape Regular tape Swiss Army Knife Screwdriver and small wrench (in case a stand is wobbly) If I can fit it, a collapsible full music stand (never know if there will be enough stands at a performance. Trust me this has happened to me a lot.) Small camera Extra batteries Small travel toothbrush and toothpaste (doesn't hurt to brush and rinse twice before a performance) A sheet of the key signatures (I still can't memorize them all) If I have to march gloves and black socks. Actually I should carry extra gloves and socks. Never know if someone will forget one of them. Basically I have a small survival kit.