What kind of automations have you found necessary? Any time I think about getting into it, I can only think of automations that sound silly or extra but nothing truly time-saving.

Not the user you replied to, but for me:

Open blinds in the morning, shut them at sundown.

Turn on porchlights after dark if I'm not home. Turn them off 10m after I'm home.

Turn HVAC up/down when I leave the house, revert when I get home.

Unlock doors when I arrive home. Make sure they're locked when I leave.

How does home assistant track know if you are home or not? Is it tracking your location?

You can set up zones based on your phone's GPS (there is a Home Assistant mobile application that can report data back to the server), or you could set up an automation based on whether your phone is connected to your home's wireless network. Or probably even via some Bluetooth beacon.

Where I live we have frequent scheduled power outages, I use that to schedule when and how far to charge my batteries

South Africa?

I've documented all of the automations I have set up at my Airbnb: https://www.linquist.com/airbnb/automation

Turn off ac in the morning and back on before I come home. Saved me about $70 a month

I got tired of tuning the speed on air purifiers at home. Since outdoor PM levels can change up to 1000× in a single day, you have to adjust accordingly, and it takes a lot of attention to do that.

So I set up automation for that based on a few parameters: indoor and outdoor particulate matter levels (current and averaged over the last hour), noxious gas levels based on third party monitoring, wind direction and speed, and the weather forecast for the next few hours.

Probably doesn't apply to others here, though.

I hook tons of stuff up to HA and I love it. It's great with Sonoff switches flashed with Tasmota.

I've moved on my Sonoffs from Tasmota to ESPurna and finally to ESPhome which I find excellent.

Which switches models? Zigbee? I am still fighting with them (unflashed at the moment)

I'm using the S31's. Fairly easy to pop open and flash if you've got some alligator clips and one of those flash programmers (eg https://www.amazon.com/gp/product/B075N82CDL/ref=ppx_yo_dt_b...).