my experienced with old myvi (2009) ac, the 1st time its not cold after 8years bcoz of punctured top hose for the condenser.
replaced it, top gas oil, its cold already.
2nd time, magnetic clutch broken (the rubber holding the magnetic clutch plate disintegrated). diy replaced, working good again.
3rd time , not cold when stop, fan motor weak. upgraded with bigger motor fan set (halfcut). good already.

then gave the myvi to brother. ac not cold. he went topup gas and oil, good cold back again..