The standard does recommend that the period between service visits should be based on a risk assessment taking into account serval factors including the environment that the system is installed in and the type of system, along with any other factors that could contribute to the long operation of the system.

But the longest time between service visits is recommended not to exceed six months. Confusion sometimes results from the fact that, under the British Standard it is only necessary to verify the operation of each manual call point, fire detector and sounder every twelve months; this work can be spread of more than one service visit.