Unless there is a leak in the system, most don't have to be charged for a very long time.

If you feel that the conditioned air coming into the room(s) feels too warm, call an HVAC contractor to come out and have a look at your system.

You can also find one here by going to the top of the page and click on "Find" then "Contractors" then enter HVAC Contractors followed by your city and state.