I don't think the OP is talking about low-level OS stuff like perhaps a flaky hard drive, but about installing the things that turn a vanilla machine into your

I don't think the OP is talking about low-level OS stuff like perhaps a flaky hard drive, but about installing the things that turn a vanilla machine into your working environment, plus being able to sort out things when something goes wrong with that environment. If you're in IDE Foo all day every day, you should know your tool enough to fix it when it goes wrong. I've not had them myself, but I have talked to other sysadmins who've had devs that couldn't install their own IDE. These people weren't seniors, admittedly, but they were still drawing pay...