Capacitor ?'s

When using a capacitor does it have to charge each time your car is turned on, and then does it decharge when you turn it off? If this is true, then when i pulled out my capacitor from my car, should it be decharged or still be holding a charge? If it is like a battery i am assuming it's better to keep it charged so it will last longer but i don't know. SO.........Should i decharge my capacitor (if it's not already) or should i keep it how it is(charged)?rock and roll!!

Once you disconnect the capacitor from its power source it will slowly discharge. I have stored caps for years (with out a charge) and hooked them back up and they worked with out any problems