Re: "five year old servers and four year old PCs"
> So that's supposed to be a problem ?
Right? At previous $job the central IT group enforced desktop & laptop PC changes about every 2-3 years, primarily because whatever next version of Windows they were mandating either wasn't supported on the deployed kit, and/or because Windows N+1 consumed even more memory than N and the status quo gear didn't have enough.
Meanwhile I used the same 5+ year-old PC and a hand-me-down laptop with Linuxes and would have kept on that way just fine if IT hadn't declared any non-Windows device as unsupportable and locked them out of the LAN.
This wasn't a small place, either; the amount of PC gear they churned through (and in many cases, outright wasted) was appalling. Almost entirely because of central IT policy and bureaucracy.
Meanwhile in the datacenter and labs we regularly ran servers for 5+ years, sometimes longer when it made sense vs. rackspace, power, duties, fleet size + spares, etc.