I agree with Zooker on this.
If your route has compulsory points then you report where you are then the estimate for the next compulsory point. The estimate or a report at a non-compulsory point would only have to be given if requested by ATC.
It would only be requested if the ATCO wanted an intermediate point to get a pass to climb or descend, to prove a separation or possibly if the time elapsed between the compulsory points was greater than that allowed for reporting action for operation normal checks.