Nedarim 4 - Or perhaps, "Do not delay" does not apply?
For the past two pages we were discussing why the prohibition of "Do not delay" applies to a Nazir. We even found a special case when it would apply - when one says, "I will be a Nazir before I die."
However, is that even true? After all, the laws of Nazir are an unusual innovation not found in other parts of the Torah. What is unusual? - The fact that one can complete his vow of a Nazir by offering only one of the three required sacrifices; this is not ideal, but acceptable. You might have thought that just as the laws of a Nazir are more lenient here, so too they are more lenient in regards to the "Do not delay" requirement. For that we have to rely on the rule of similarity: vows and Nazir are similar; as such, all laws of vows apply to the Nazir.
On the other hand, maybe applying the rule of similarity is an overkill? Perhaps a simple rule of "context" would work? "Context" means if we find a law in one case, it applies to all other similar areas. For example, the father can annul a vow of his daughter. Therefore, he should be able annul other similar vows, such as if she wants to be a Nazir (technically, "Nazirah"). - No, that logic would not work: vows are stricter in that they have no limit, but a usual Nazir is for thirty days. So maybe that's why father needs the power to annul a vow but not a Nazir vow. Thus, we are back to using the rule of similarity.
Art: Father And Daughter In A Landscape by Pierre Duval-Lecamus