Here’s what the council said about religious communities praying the Hours:
Communities obliged to choral office are bound to celebrate the office in choir every day in addition to the conventual Mass. In particular:
a) Orders of canons, of monks and of nuns, and of other regulars bound by law or constitutions to choral office must celebrate the entire office.
b) Cathedral or collegiate chapters are bound to recite those parts of the office imposed on them by general or particular law.
c) All members of the above communities who are in major orders or who are solemnly professed, except for lay brothers, are bound to recite individually those canonical hours which they do not pray in choir.
Perhaps any religious reading would offer commentary on this. How has it gone since the council? What are your recollections before Vatican II?