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.
![](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_v1WAG8ee7MkJc1pzZCRBHLCrC6-LcZ4O8tm0CHdfYcg7zo_BhoGXgomJhu5L_7gx3bfjzQg4xfPvqIjqgO_ek7IEydm_oiWgRQfgkffMI3xbKtLb0Gu2EVPz_t1PNdAg47_Sd9LYX0KZ4HC_w=s0-d)
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.