Chapter VII-A. Choice of Mass
314. On solemnities the priest is bound to follow the calendar of the church where he is celebrating.
315. On Sundays, on weekdays of Advent, the Christmas season, Lent, and the Easter season, on feasts, and on obligatory memorials:
a) if Mass is celebrated with a congregation, the priest should follow the calendar of the church where he is celebrating:
b) if Mass is celebrated without a congregation, the priest may choose either the calendar of the church or his own calendar.
316. On optional memorials:
a) On the weekdays of Advent from December 17 to December 24, during the octave of Christmas, and on the weekdays of Lent, apart from Ash Wednesday and in Holy Week, the priest celebrates the Mass of the day; but he may take the opening prayer from a memorial listed in the General Roman Calendar for that day, except on Ash Wednesday and during Holy Week.
b) On the weekdays of Advent before December 17, the weekdays of the Christmas season from January 2 on, and the weekday Mass, the Mass of the saint or of one of the saints whose memorial is observed, or the Mass of a saint inscribed in the martyrology for that day.
c) On the weekdays in Ordinary Time, the priest may choose the weekday Mass, the Mass of an optional memorial, the Mass of a saint inscribed in the martyrology for that day, a Mass for various needs and occasions, or a votive Mass.
If he celebrates with a congregation, the priest should first consider the spiritual good of the faithful and avoid imposing his own personal preferences. In particular, he should not omit the readings assigned for each day in the weekday lectionary too frequently or without sufficient reason, since the Church desires that a richer portion of God's word be provided for the people. 
For similar reasons he should use Masses for the dead sparingly. Every Mass is offered for both the living and the dead and there is a remembrance of the dead in each eucharistic prayer.
Where the faithful are attached to the optional memorials of Mary or of the saints, at least one Mass of the memorial should be celebrated to satisfy their devotion.
When an option is given between a memorial in the General Roman Calendar and one in a diocesan or religious calendar, the preference should be given, all things being equal and depending on tradition, to the memorial in the particular calendar.