We have mentioned this topic elsewhere, but it deserves its own section. Do not leave your instrument in an unattended vehicle. Ever. Even if it's in a locked trunk and out of sight. There are two important reasons for this. First, the extremes of temperature that can be present in a closed car can damage your instrument. You should minimize the changes in temperature and humidity through which your instrument has to pass, and cars are a particular danger in this regard. Second, there is always the danger of theft from your vehicle. Many insurance policies will not cover the loss of your instrument if you have left it in a car, because of its vulnerability in this situation. Do yourself and your instrument a favor, and take it with you when you leave your car.