1st Diviner’s Fortune (Su): You can touch a creature as a standard action, giving it an enhancement bonus to a single attack roll, skill check, ability check, or saving throw equal to your caster level. This bonus lasts 3 rounds or until used. Once a creature has benefitted from diviner’s fortune, it can gain no further benefit from this ability for 1 day.
Does the target creature get to choose to use the bonus or not, or does it apply to the next eligible roll even if the creature would rather save it for something else later in the round ? If so, perhaps adding the phrase "of its choosing" between "saving throw" and "equal to your caster level" would help clarify.
If the creature does not use the bonus and it expires after three rounds, the creature has not benefitted and is still eligible to have Diviner's Fortune used on it again immediately, correct ?
Edit: dang speeling