For anyone wanting to know more about the “ThoughtAsylum” stuff for Drafts that Alex mentions in this episode, I’ve posted some details in a separate topic.
Awesome episode, I really enjoyed it and Alex was an awesome guest who has some really interesting automations going on.
I will definitely have to check out Drafts in more detail. I have it installed and like it so far, but I really need to dive into it deeper!
EDIT: Fix typos, seems like I was not able to hit the correct keys, when I wrote it.
Serious question:
I’m overwhelmed just listening to this. How do you all find the time to maintain all those intertwined systems?
iOS Shortcuts, Toolbox Pro, Scriptable, DataJar, Pushcuts, native web-APIs or access to them via Zappier or IFTTT. Throw in HomeKit, compatible HomeKit products, light fixtures from different brands using Zigbee, various apps like the ones from Aqara or Eufy to control their walled off products, various HomeKit apps to access the data (like HomeCam, HomeRun), Homebridge to orchestrate it and other things hosted on a Raspberry (PiHole etc.) or a NAS (Synology, QNAP) plus the required network infrastructure (Ubiquite, Eero, …). In addition to local macOS Automator scripts, Alfred workflows, Hazel scripts, Keyboard Maestro automations and to top it off, Streamdecks.
For data: DevonThink indexing, various sync services such as Dropbox, iCloud, Google drive in addition to data scattered across a plethora of services like Airtable or Toggl. Throw in note taking apps like Apple Notes, Notion, Mindnote, Obsidian and productivity tools like Things, Fantastical, Spark, Omnifocus and all their various keybindings across different platforms.
And I haven’t even talked about beacons, NFC and locally scheduled automations …
For me the trick is not to need maintenance. Set it and forget it. Of course, I love to tweak things - but if something works I will just leave it alone, and let automatic updates take care of the maintenance 
I don’t have a huge amount of home automation, but I have stuff all over the place and run different platforms at work (Windows, *nix, and web systems) than I do for my personal stuff (Apple, RPi, Web, various others), so I can fully appreciate how it can all add up over time. But scale and complexity does not necessarily mean that it becomes difficult to maintain. Especially if you are conscious of the growth, it takes place over time, and you have already been through the troubles that letting t get away from you can incur 
I think of the automation scripts, tools and apps I have to hand (or have created) as my own personal organisation in that I try to put together hierarchies and manage them. After all, without them, I’d need an organisation of non-digital minions to do my bidding to get everything done on time and correctly. Keeping them ‘organised’, or at least trying my best to keep them organised also makes them easier to maintain, duplicate and swap out - again, just like a ‘real’ organisation.
I pass out the tasks and activities to do via as small a first layer as possible. But these may then control or pass on things to do to other workers in the organisation, and there’s nothing to stop me from going to them direct when necessary. Sometimes the chains may be long. Sometimes they cross over and are used from multiple places. But they work together as processes, just like in a more traditional, physical organisation.
On top of that, anything that isn’t trivial or obvious tends to get some documentation to go with it. Where this documentation lives depends on what it is, and who else might need it, but as much as possible, I try and centralise and cross-reference that too. My day jobs have always involved a lot of writing documentation, so fortunately, this is ingrained in the way I work with my own projects too.
I think the only practical threshold is when you have to start mapping your personal systems out with data flow diagrams and environment diagrams that would take up multiple A3 pages in 8pt font right? 