A method of timer-based registration prevents timer-based registrations that are not needed from being sent. A history is maintained of time instances of implicit registrations transmitted by a mobile station over a communications network. If an elapsed time between a pair of successive ones of the time instances in the history is not less than a registration period with the network, a timer-based registration of the mobile station with the communications network is initiated after the expiry of a random time value less than the registration period. Otherwise, a timer-based registration is initiated after the expiry of a time period equal to the registration period.