Never, unless you suspect of not cooling then there is a leak somewhere. A repair will need to be performed before recharging.
5yrs
Never! If it's low on refrigerant it has leaked.
It is recommended to refill your air conditioner with refrigerant only when there is a leak or when the system is not cooling properly. Overfilling can cause damage to the system, so it is best to consult a professional HVAC technician to determine the appropriate timing for refilling refrigerant.
Incorrect refrigerant charge?
No, it's not your fault. It's just running too much. Often this can happen due to the level of refrigerant in the air conditioner being too low, perhaps due to a small leak. The air conditioner should be checked out by a reliable cooling repair person.
The air conditioner on a 1999 Buick Bonneville will often leak due to a damaged seal. Over time they will slowly break down and allow refrigerant to escape.
10 years
An AC unit should be recharged with refrigerant only when there is a leak or a noticeable decrease in cooling performance. It is not necessary to recharge the refrigerant regularly to maintain optimal performance.
Never unless you have a leak. I haven't put a drop in mine in over 13 years.
As often as its needed to get the room set to your set tempature.
Never, an air conditioner is a closed system. If you need to add refrigerant you have a leak that needs to be repaired. In theory you should never have to add freon. but there can be some residual loss. maybe after five to ten years.
Freon (or any refrigerant) only needs to be replaced if it is low. You can have the refrigerant checked at most auto repair shops and they can tell you if it's low. If it is, they should also check for leaks as it is a closed system and does not normally lose refrigerant.