Most undertook such vows for only a set period of time, but a few, such as Samson, Samuel, and John the Baptist, were lifelong Nazirites.
Enamikul juhtudel anti nasiiritõotus teatud perioodiks, kuid mõned üksikud, nagu Simson, Saamuel ja Ristija Johannes, olid eluaegsed nasiirid.