Write down what pressure your tires are supposed to be a check them every few times you fill up on gas.A log or some other system for tracking your gas mileage. Useful when you go to an ATM.Safety, Maintenance, and Legal:Your auto insurance cardYour registrationJumper cablesA spare tire, a tire iron, and a jackTire pressure gauge. Stay sanitary, and keep crap off of your floor mats.A pen. When most people are in their car alone, they pick their nose because it's been bothering them for a while and they are around people. Wash them with soap and water, then dry with a cloth every so often.A pack of travel Kleenex. Sometimes you don't have your phone on you, or you'll want to let someone listen to something while your phone is in use by someone else.Sunglasses with clean lenses. By 'safe,' I mean albums that you've liked for a while and won't get tired of. Personal Items:Several dollars in change for parking meters, tolls roads, and cart deposits at groceries and airports.A car charger for your phone and an aux jack, cassette adapter, or some method of playing audio over the stereoA few 'safe' burnt CDs.