Under an Agile methodology, standup meetings occur:

The daily standup is a time-boxed, typically 15-minute ceremony held every working day in Agile and Scrum frameworks. Its purpose is for each team member to share what they did yesterday, what they plan to do today, and any blockers they face. Daily frequency ensures rapid feedback loops and early identification of obstacles, which is central to Agile's iterative and adaptive approach.

Twice daily is not a standard Agile ceremony cadence; it would create unnecessary overhead and interrupt flow.

Weekly cadence describes a less frequent meeting such as a sprint review or retrospective, not a standup.

Ad hoc meetings occur as needed and are not the defined cadence for standups, which are scheduled and predictable.