The Air Condition in my 2007 Dodge Grand Caravan (has 42k miles) was not cooling as good. The mechanic said the AC required a Freon recharge every year !! Is he correct? It's good now after he recharged it.
You have a leak. You need to take it to a shop where they can put dye in the system. Then they can use a black light and find the leak where the dye came out.
No it does not need a charge every year. It only needs a charge when there is a problem with it. It does however need to be inspected once a year to keep it in good operating condition.