Do you virtualize/pool host to separate function from hardware? If yes, then go nuts shutting off hardware as needed for service.
Otherwise, the correct answers are “annually as part of a practical DR review”, “only when the electric company cuts you off for non-payment”, and “as often as needed to keep a spouse off your back”.
Apart from the grounding issue, my 16" Pro has done things alone that most of my peers use a laptop AND a desktop to get done. But yeah, if you're not processing a ton of realtime video, or saturating thunderbolt with network traffic or something, then the Air could do any 2-3 of the 8 things I'm doing at once admirably. And I'd probably be less pulled in all directions. lol.