iPhone: Apple Reminders

  1. Open the Reminders app and create a new reminder, or open an existing one.
  2. Tap the "i" info button next to the reminder.
  3. Turn on "Location."
  4. Choose "Arriving" or "Leaving," then search for the address, or tap "Current Location" if you're already there.
  5. Adjust the radius if you want (the default is usually fine for a house or office).
  6. Save. The reminder fires the next time you cross that boundary.

You can also do this entirely by voice: say "Hey Siri, remind me to grab my charger when I leave home," and Siri sets it up for you, as long as "home" is already saved in your Contacts card.

Android: Google Keep

  1. Open Google Keep and create a new note, or open an existing one.
  2. Tap the reminder bell icon.
  3. Switch from the time tab to "Pick place."
  4. Search for the location and select it.
  5. Save. Keep will notify you when you arrive at that location.

Note that Keep's built-in location reminders are arrival-only; there isn't a native "when I leave" option the way Apple Reminders has. Some Android phones also offer location reminders through Google Assistant directly ("remind me to take out the trash when I get home"), which works similarly.

Where the native options run out

Both of these are genuinely useful for a single, one-off reminder. Where they run out is anything beyond that:

If what you actually want is a checklist, several items, that shows up automatically every time you leave or arrive somewhere, that's a step beyond what either native tool is designed for.