The "24:00:00" format is most frequently found in environments where a day's end must be clearly defined:

Used to mark the very start of a new calendar day.

While they represent the same physical moment, the choice of notation depends on the perspective of the time interval:

Used to mark the exact conclusion of the current day. It is the only time where the hour "24" is permitted, and it must be followed by "00" for minutes and seconds. 2. Common Use Cases

A store open "00:00–24:00" is open for the full 24-hour cycle.