No two lunations are the same length. They run from 29.27 days to 29.83, thirteen hours between the extremes.

29.53 days is an average, not a timetable. The orbit is an ellipse and the Earth-Moon pair is itself swinging around the Sun at a changing speed, so every cycle differs. Within a single lunation the four segments between phases can differ from each other by more than a day, which is why the quarter moons never fall on tidy dates.