Re-gassing an air conditioner will never be necessary if it is installed correctly.
However, if the pipe connections are not ÔflaredÕ (a type of compression fitting) properly or tightened to the correct torque, or if the pipes themselves degrade over time for some unforeseen reason, then they may leak, which is the most common cause of needing to re-gas an air conditioner.
Terms such as 'stale gas' or 'expired gas' are not something that occurs in air conditioning units.
If there is a gas leak in your air conditioning system it should be inspected by a qualified air conditioning technician. Please speak to your Daikin Specialist Dealer for more information.