Asklemmy

If they're using Home Assistant then it's pretty straightforward. You can either have the devices report back their location and update based on a Geofence or you can check and see if everyone's on the wifi or not

Since we're an iPhone family I use iCloud3 in HomeAssistant to track our devices. After setting that up and associating the phones with people in HA it was just a matter of creating triggers based on us entering the home zone:

alias: Somebody Arrives Home
trigger:
  - platform: zone
    entity_id: person.jack
    zone: zone.home
    event: enter
  - platform: zone
    entity_id: person.jill
    zone: zone.home
    event: enter

We live at the end of a dead-end, so I set up the home zone to extend down the road a bit. That gives iCloud3 enough time to figure out we're home and trigger the automation in HA while we're still approaching. I combine the above with a check to see if it's roughly sunset to sunrise, and if it is then turn on the outdoor lights.

For doing things like turning off the lights when nobody is home, I have a similar trigger for everybody leaving the home zone, followed by a conditional that verifies everybody is away:

condition:
  - condition: or
    conditions:
      - condition: template
        value_template: >-
          {{ states('person.jack') != 'home' and states('person.jill') !=  'home'  }}

I came up with these myself over time, they started 10+ years ago using a Mac platform called Indigo, but since moving into our new house a year ago I've switched over to Home Assistant as well. I have a background that includes 10 years of software development & another 15 of IT, so these sorts of things come fairly easily to me when I think about it a bit.

My wife and I use iPhones and I found iCloud3, which is a great add-on that tracks locations based on those devices. I started out with the washer/dryer notification with the simple realization that we regularly forgot about laundry in our washer in the basement since we'd forget that we had started a load. So I figured out how to have HA send us alerts when the washer or dryer finished. But I quickly realized that wasn't all that useful if one or both of us was at work, shopping, etc. I then realized I could set up a trigger based on a time schedule that checks if we're home or not, and only sends the alert if we are. So I have a HA automation that is triggered every 10 minutes by a timer, but the timer is disabled by default. That automation uses iCloud3 to check if either of us are home. If we are then the automation calls a script to notify us. If we're not home then the automation resets the timer for 10 minutes. When the washer completes it triggers an automation that just starts that timer running. That gives us a little time to park the car, bring in any groceries, etc. before being reminded that we have laundry waiting.