Re: Friday rule
I agree, and not being an engineer I wouldn't dare not. But there's a caveat. A lot of perfectly good, non-system critical, non-networked devices were "millennium-proofed" at significant cumulative cost. Or simply mothballed/dumped. There was no rational risk-assessment performed on these devices.
PCs ( some quite elderly) used for word processing did not need any of that. What was the worst possible outcome? They'd fail to boot in January 2000. Improbable, but manageable. No different to when a cmos battery fails.
And I did take one or two out of mothballing a few years later - they were useful for taking off-site for kids to use etc. Worked perfectly of course. (Though the CMOS battery failed, in at least one - might have been coincidence).