Which mode for - At Home but often using the garden

If you are in home mode and you open the door, the alarm will go off.  Ways around this:

1) start with the system off.  Open the door.   Turn to Home mode.  Never close the door, because if you open it again,  the alarm will go off.

2) Change the sensor on that door to only be active in AWAY mode.

3) As you say, remember that the door is alarmed and you have to turn the alarm off to open it.

4) With the system off, slide the door sensor out of its base and set it aside.  Set Home mode.  Remember to replace the sensor when you want that door protected again.

5) Modify the sensor with a switch which you can use to "turn if off" (this will void the warranty on that sensor).  Remember to switch it back on when you want that door protected again.

leave the door open BEFORE you set the Alarm to "HOME".  That single door will *not* arm until the door is closed (the rest of the system will arm normally).

As long as you don't close the door - you should be fine.  If you do close the door - system will arm and you will get a warning/alarm if you open the door again while system is still in HOME mode.

Using the app or the keypad, you can change the setting of your front door sensor to disabled when in Home mode. It's easier to do this with the app because you can change individual sensors without turning off your entire alarm system.

The thing is you'll need to remember to set the sensor back to Alarm when you are going to stay inside, for example nighttime or going to bed.

SS really needs to have two Home modes. One for daytime when you might want some sensors disabled or set to secret alert, and a night time mode when you would want those sensors enabled.

Not "two Home modes",  that would  be terribly confusing.  But a third "Custom" mode, yes indeed.

By the way, the odds are less than 1% we would see this before SS4.  It would almost certainly need new hardware.