I have always been used to the 10 mn rule in the first hour and then you can ramp back after that.
When you hit the 24th hour in is usually a bit less to report but an hourly report should be given if
only to state that there are no new updates from the incident.
The major events rule I think applies no matter where you are in the world. As another poster said,
if your dispatch does not ask for an update, provide one from the CP.
If you fill out your Log with all info from sitreps it will aid you in AARs and in determining what you have done and when.
Good luck and hope since this original post you have gained some confidence in commanding at large incidents!