How long should jumper cables be left on when jumping a car?

first,don't hook em backwards,next,unhook em once the dead vehicle starts(CAREFULLY).also,there is a certain way you need to connect them AND disconnect them(CAREFULLY).NEVER LETTING ANY OF THE FOUR METAL CABLE ENDS TOUCH ANYTHING BUT YOUR HANDS and the correct place to jump start!!! How to Hook up Jumper Cables: 11 Steps (with Pictures) www.wikihow.com/Hook-up-Jumper-Cables