An image forming apparatus includes: an ink-jet head including a storage that stores phase transition ink, the ink-jet head forms an image on a recording medium by ejecting the phase transition ink; and one or more hardware processors. The one or more hardware processors change a driving condition of the ink-jet head for a case of ejecting the phase transition ink on a basis of a first reading result of a pattern image formed by the ink-jet head; estimate occurrence of a state change of the phase transition ink in the storage when the driving condition that is changed satisfies a predetermined condition; and determine whether a lifetime of the ink-jet head is over in accordance with whether the occurrence of the state change is estimated.