I use "When vacated contact ground xxx.xxx". I always use that once I see the aircraft has broken enough and is taxiing at a constant speed to avoid disturbing the pilot at a high workload moment (specially helicopters). What I expect with that is that the aircraft switches frequency when is vacating the rwy, turning into twy and is aware that he will be able to pass the HP without any issue.I want it to remain in TWR frequency until the very last moment but to contact GND before having to stop after the exitway, where the traffic has to stop if no further instruction has been given, in order to receive taxi instructions.