[NiftySVX]

Refrigerant never gets used, it's like air in a tire. It is inside a sealed system If it leaks out, there is a problem. I recently worked on a customer's camry that had 467,000 miles on it. Compressor was dead but it still had over a pound of 134a in it, factory charge was 1.2 lb.

Using the a/c will not make it deplete, but it can exacerbate a leak because of the pressure increase from it's use. DO NOT charge a car unless you know how much is in it. If you over charge it, you can make the compressor pump in excess of 500 PSI which can cause hoses to explode and could seriously injure you, or even kill you. No lie.