Balance the inconvenience of service interruptions with the cost of reducing the interruption.
Engineers and other staff can work at weekends / nights / popular vacation times / public holidays, but at an increasing cost. There's also a limited total number of engineers, so it will help to have a steady amount of work (i.e. permanently employed staff).
Engineers and other staff can work at weekends / nights / popular vacation times / public holidays, but at an increasing cost. There's also a limited total number of engineers, so it will help to have a steady amount of work (i.e. permanently employed staff).