Starting with a long mishnah: the phrasing of the vow prohibiting benefit makes a real difference, even in private property. What happens when the property is available for public use? How can one be sworn of use or benefit from them? The mishnah defines municipal works in this context. Plus, different locales have different expectations and requirements. Also, on the people of the Galilee - whom the Gemara calls "contrarians," who regularly made nedarim, swearing off each other's property! Plus, a second mishnah - with the case of a grandfather who swears off benefit from his son, which makes things difficult when the son is marrying off the grandson. A work-around is needed.