Why is the height of the geyser and their operating time different?

Geysers are a late example of volcanism, namely hot springs that emit hot water and steam instead of lava. The height and time of the erupting jets depends on the type of geyser, they are regular and irregular. In regulars, the time and height of the ejection always move according to the same principle and do not change, while in irregular ones, the time between eruptions can be from a couple of minutes to several hours, and the rest time can reach 2 days.