Re-Charge aur condition on 2008 Chevrolet Avlanche

You can buy a can of refrigerant with a gauge at the auto parts store, and follow the instructions on the can and hope it holds, or you can do it right and a mechanic reclaim the refrigerant, check for leaks, pull a vacuum on the system and recharge with the correct amount of refrigerant.

Agree. If it needs recharging there's something wrong with the system. That needs to be fixed before the system will hold refrigerant and work properly.