The time they had to study the material varied per round.

The number of points required for an award night varies per hotel.

These are a little harder to pinpoint exactly because they often vary per month.

The upper and lower frequency limits of human hearing vary per person.

The total number vary per the length of a ship.

The color and length of the shorts varies per school.

The range and possible area of effect damage vary per ability.

The dialect was used in trade activities, and may have varied slightly per region.

The passes are valid for one month, and the number of travel days available varies per country.

The amount of words provided in the lists varies per puzzle.