On several threads, it has been asked which masses from the Graduale Romanum, or Kyriale, should be sung on particular feasts days and seasons. It has been often noted in reply that directions in the Graduale are suggestions rather than a hard and fast rule. But while there is legitimate freedom in this area, part of the context for the Graduale's permissiveness was varying local usages that were very prescriptive. The disclaimer in the Graduale's accommodates both flexibility in the selection of the chants of the ordinary and these particular local usages.

As an example of a local usage, here is a summary of indications for mass ordinaries for Rouen, France, published in 1937. These are very pinpointed and to not seem to allow for exceptions. Note that the Credo is specified in every case.

- Mass 2 (Kyrie fons bonitatis) with Credo 3 - Solemn feasts of the Lord: Christmas, Epiphany, Easter, Ascension, Pentecost
Footnote: For Christmas midnight mass, sing Mass 9 below.
- Mass 4 (Cunctipotens Genitor Deus) with Credo 3 - Doubles of the 1st class, Holy Thursday and solemn votive masses
- Mass 8 (De Angelis) with Credo 4 - Doubles of the 2nd class and feasts of holy Angels
- Mass 10 (Alme Pater) with Credo 4 - Doubles and double majors
- Mass 17 (1st Kyrie) with Credo 1 - Sundays of Advent, Septuagesima and Lent
- Mass 11 (Orbis factor) with Credo 6 - Sundays after Christmas and Epiphany, and in Octaves other than of the Blessed Virgin
- Kyrie "ad libitum" 7 (Splendor æternæ) with rest as Mass 17 above - Passion and Palm Sunday
- Mass 1 (Lux et origo) with Credo 4 - Paschal time
- Mass 12 (Pater cuncta) with Credo 1 - Sundays after Pentecost and semidoubles
- Kyrie (new) with remainder from Mass 8 with Credo 3 - Feasts and solemn votive masses of the Blessed Sacrament and Sacred Heart
- Mass 9 (Cum jubilo) with Credo 3 on 1st class feasts, otherwise Credo 4 - Feasts and masses of the Blessed Virgin
- Mass 15 (Dominator Deus) - Simples, ferias in Paschal time and votive masses
- Mass 18 (Deus Genitor alme) - Vigils, rogation days and ferias throughout the year, including Lent

The list is in the order presented in the book. I have added the mass numbers from the Graduale for clarity - these do not appear in the original.

From Paroissien Romain a l'usage de Diocèse de Rouen, No. 3800, (1937), published by Maison Mame with extensive extracts from the Paroissien Romain (No. 800) published by Desclée & Co. used with permission.