Given maintenance that is tedious, invasive, time consuming and difficult to schedule:
If you are told a system will be out of service next week and you defer critical maintenance, it will never go out of service.
If you are told a system will be out of service next week and you perform critical maintenance it will go out of service the day after your maintenance is complete.
If you are told a system will be out of service next week and you defer critical maintenance, it will never go out of service.
If you are told a system will be out of service next week and you perform critical maintenance it will go out of service the day after your maintenance is complete.