Does the expiation for an oath of persistence (nذر اللجاج) cease to be incumbent upon the one who made the vow after performing it once, or is it due from him every time he breaks the oath?

Undertaking a vow is disliked due to the established prohibition against it. The one who makes a vow of obstinacy (nadhir al-lajaj) has the choice between fulfilling his vow or offering an expiation for an oath (kaffarat yamin). One expiation is sufficient, even if the sinful act is repeated, unless the wording of the vow indicates repetition.