Thanks for the feedback! Noted this down for future research, although plase see my short answers below

In my experience, PCs are often not replaced in the office due to broken components but more ammortisation of hardware that then renders them too slow for operation. Either that or the lease terms are up on the hardware and they are returned to the vender.

There are some great monitoring tools to ensure that hardware doesnt reach crazy high temps, T Throttle comes to mind, that maybe can be bundled to ensure that temperatures are managed.

Of course this is different for every company and depends on the IT setup.

Electricity is tough, but once again in my experience, electricity usage can be monitored and plotted in real time through building management and the utility provider. Case by Case basis though.