Re: i take it you mean...
Yes. Obviously you don't just shut things off willy nilly. You'll be using smart switches and you'll know what device/appliance each one is assigned to. You'll use your brain when concocting automations. Sure you'll need to purchase the switches but the hardware to run Home Assistant can often be picked up for no money and a bit of effort from Freecycle/Freegle type places. Insights gleaned from monitoring the power draw through the switches will eventually lead to better scheduling of appliance usage such that shutting things down becomes either unnecessary or rare.