Sentence examples similar to not obligatory now from inspiring English sources

It's not obligatory".

Music is not obligatory.

Rubbing noses is not obligatory.

Bookings are recommended but not obligatory.

It may be convenient practice, but it is not obligatory.

It's not obligatory, but it's appreciated.

(Gifts are certainly not obligatory). What says Miss Manners?

But the historical context was not obligatory in the curriculum.

And yet, and yet... "liking Shakespeare is not obligatory".

It's not obligatory, but it is expected".

But they are not obligatory for other tournaments, only recommended.