Hi,
I’m have a remote switch, which I would like to control my alarm system?
The remote is a 433 mhz remote, used with RFLink, and is added to HA as a lightswitch.
Now how do I setup this automation the smartest way?
As one automation watching for a state change, and an { if state = on -> set alarm = armed else set alarm = disarmed }?
Or as two automations, if state = on set alarm = armed and if state = off set alarm = disarmed?
What would be the best way for this?
Automation triggered by state change, service_template in your action to arm or disarm the alarm based on the state.
Templates are definitely fancy and I’ve used my fair share of them but is there a true advantage to having one automation over two?
When something is cut and dry, turn something on at 10 and then off at 12, is there a downside to two distinct automations? Putting personal preferences aside.
Do more automations take more file handles or memory or listeners? I and sure they do but is 10,20 or even 100 inconsequential?
Inquiring minds want to know. 
If there is i’m sure its not a big impact, but i’m not too sure really. I use a single one when I can, but a lot of the times I end up needing to use 2 (or just wanting to because its easier to read I guess)… or just writing a python script depending on the complexity of what i’m trying to accomplish.
A lot of people tend to ask to how get their thing down to 1 automation so I tend to give this suggestion out a fair bit