In the Dominican Office, for the Vigil of the Nativity of St John Baptist, the only special parts appointed are three lessons on the Gospel of the Vigil Mass; all else, from Matins through to None is simply from the Psalter and the Ordinary – even the Collect is but that of the preceding Sunday. In this, the Dominican varies from the Roman Office – the latter uses the Vigil Collect for the Hours, while the former keeps it for 1st Vespers only.
Having come in from work, I first read Terce to None, then had just time to pray 1st Vespers before the evening Mass, which did indeed turn out to be a celebration of the Vigil. (Lauds I'd prayed before leaving for work, but press of business made me leave Prime till lunchtime!)
It made me think of the logic of the Dominican restriction of the Vigil Collect to Vespers: of old time, Vigil Masses were celebrated after None, immediately before Vespers, and at the end of Mass was sung not Ite missa est, Go the Mass is ended, but Benedicamus Domino, Let us bless the Lord, as it were exhorting the congregation to remain for the ensuing Office.
Properly speaking, the Vigil was a plain, sober, penitential day, a fast in preparation for the feast; therefore, the ferial office is said, complete with the kneeling prayers of Kyrie and Our Father at each Hour; there is nothing proper to the Vigil except for a homily (to be read at Matins) on the Vigil Gospel that would be finally heard in full after None in the afternoon.
I was so glad, so glad, to get to a weekday Mass: what a decline from my former practice of almost daily Mass; what an inexpressible Gift of God. Deo gratias.