We test for leaks, recharge the system, and repair or replace compressors, condensers and blower motors.
If your air conditioning went from cold to cool over a couple of summers, that is a slow leak. Topping it off without finding the leak just postpones the problem and puts refrigerant into the air.
We pressure test the system, find where it is escaping, and fix that first. Then we recharge to the manufacturer's specification rather than guessing.
Blowing warm on one side, weak airflow, or a smell when the fan comes on are all worth a look before July.