I installed Home Assistant to solve exactly one problem: a hallway light that nobody ever remembered to turn off. That was a month ago. Since then I have integrated the heating, the front door, three flavours of smart plug, the energy meter, and for reasons I cannot fully reconstruct, the washing machine. The hallway light, I should note, still occasionally stays on all night, because the automation that controls it depends on a motion sensor whose battery I keep forgetting to replace. There is a lesson in that somewhere.
The thing nobody warns you about Home Assistant is that it's not a product, it's a hobby wearing a product's clothes. You think you're buying convenience and you're actually buying a project. And it is genuinely brilliant, which is the problem. The moment you automate one thing well, you start seeing automatable things everywhere, like that optical illusion where once you've spotted the arrow in the logo you can't unsee it.
I run it in Docker on the same mini-PC as everything else, which was fine until I wanted Zigbee, at which point I needed a USB coordinator stick passed through to the container and a sudden education in why my devices weren't all the same wireless protocol. Some are Zigbee, some are WiFi, one stubborn plug speaks only to its own cloud and I refuse on principle to let it. That last one sat in a drawer for a week until I found local firmware for it, which is a very Home Assistant sentence to write.
The automations themselves are where the evenings actually went. The YAML is fine, the visual editor is fine, but the thinking is the time sink. "Turn the heating down when everyone leaves" sounds trivial until you define "everyone" and "leaves" and "down" and decide what happens when one phone's location goes stale because it's on the bedside table charging. Every automation is a little state machine, and every little state machine has an edge case that wakes you at six in the morning when the bedroom lights come on because the sun technically rose.
But I'll defend it without hesitation. When it works, it's invisible, which is the highest compliment you can pay this kind of software. The heating now follows actual occupancy instead of a dumb schedule, and the energy dashboard has quietly changed my behaviour more than any amount of guilt ever did, because seeing the cost of the tumble dryer in real time is more persuasive than any bill. The whole thing is local, it keeps working when the internet doesn't, and nothing phones home unless I let it.
So yes, it ate my evenings, and I'd hand them over again. The hallway light, though. The hallway light remains undefeated. I'll get to that battery this weekend.