Followers will sometimes observe a strict diet that day, preferring to eat shōjin ryōri or "Buddhist cuisine", though this is strictly optional.

Neither of these environments is required, support for them is strictly optional.

Clothing in the gymnasium at Callisto Station was strictly optional and decorative rather then veiling.

Paying attention to the screen is strictly optional, which makes "Contact" a perfect drive-in movie.

The State line is strictly optional, the mailing system will not be affected if the State line is omitted.

Wealthy Greeks have always treated the country's tax system like a church collection plate: what they give is strictly optional.

The road rules seem quite clear: there aren't any and use of headlights (where fitted) is strictly optional.

The guitar chords for half the rock songs ever written can be learned within hours, and reading music is strictly optional.

Being able to recognize when the editor is making a joke is essential, although actually appreciating the joke is strictly optional.

Most film sequels are strictly optional.