Er, you bring the service down so you can do work on it. Somebody is doing that work. I guarantee that you'll have trouble hiring qualified people for a role t

Er, you bring the service down so you can do work on it. Somebody is doing that work. I guarantee that you'll have trouble hiring qualified people for a role that includes core hours of "2AM-5AM Sunday mornings" (or whatever other oddball time you've decided). Updating systems is precisely when you may need to have all-hands-on-deck responses. Been there, multiple times.