I have the same fear.

So everything I automate has a fallback option that exists outside of HA. My regular light fixtures, with smart bulbs? I can turn those on and off using their light switch in the event that Home Assistant is dead, like I would if they were dumb bulbs. (I seldom use them that way, but I can.)

And my basement lights have their smarts all programmed directly in the Shelly relay. It works without networking or HA or anything else. So while the basement lights are completely software-operated, they aren't dependent upon the relatively giant stack of software and complex hardware that HA brings

As long as the Shelly relay works, then the basement lights also work -- with a timer.

(That relay can fail, but it is is unlikely to fail soon. I don't worry about it any more than I do a major appliance failing: If/when it happens, I'll deal with it. It's easy to take out again.)

Interesting, I had a similar setup with smart bulbs, dumb switches and HA. My experience was that when the bulbs lose connectivity (Zigbee or Wifi in my case) you could maybe still turn them on but they would start flashing like crazy or use different colors (as indicators for their "reconnecting" state). Also Zigbee doesn't really love losing mesh nodes periodically, so turning the bulb completely off using the switch would cause the whole network to fall into broken states that had to be manually fixed from time to time.

None of the bulbs I've had (which have been a pretty wide mixture: Proprietary clown, proprietary local wifi, matter wifi, esphome wifi, zigbee) have that problem.

I just turn them off and back on one time using the switch, and the light bulb's state goes to some variation of "on" within no more than a second or two (maybe not an ideal variation of "on", but good enough to get through a dark hallway). Turn back off with the switch, and it's obviously off. On the next "on" cycle of the switch, it goes back to "on".

And while it is freshly "on", it's trying to reconnect to whatever its programmed mothership is (whether local or afar). This works every time, so far in my experience, as long as that mothership is reachable.

The only time blinkey-mode has been imparted is when I've reset things, which takes rapid iterations of off-on cycling of the light switch. (I test this all the time with the Zigbee bulb in my pantry because the light switch in there sure is convenient. It works fine, even if it has been completely off for hours or days. I just tested it again after pulling the USB zigbee dongle from HA, and the pantry light still worked fine with the switch on the wall.)

I've moved these bulbs and other widgets between houses. No issues (other than renaming things after a move). It's really been OK.

Additional background: For Zigbee in particular, I'm doing that in what is probably the least-preferred, least-effort method: I've got a cheap Chinese CC2531 dev kit that is flashed with different firmware (because that was the cheapest approach ~5 years ago), and I'm using it with ZHA in HA (because that's the easiest approach). All of my Zigbee devices have been buttons or light bulbs, all of those bulbs have been from Sengled, and none of any of them support Zigbee router mode at all. There is no Zigbee "mesh" here to speak of at all, so there's no weird interconnections to break: Endpoints talk directly with the CC2531 and that's that.

Other than some range issues (which were broadly resolved by using an old-school non-3.0 USB extension that I found on Amazon in iMac-esque coloration for a dollar), Zigbee has really been OK for me.

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But I've been migrating to wifi, anyway. My favorite light bulbs, from Athom, actually come to me with open-source ESPHome already installed...but Matter-wifi light bulbs are often a bit less expensive than those are. (Tradeoffs.)

This migration started on the basis that my old Zigbee bulbs are -- well -- old. They simply don't produce the same quality CRI that even very cheap dumb department store LEDs do these days.

Besides, I've also already built a quite lovely wifi network for my home, wherein I do not care at all about the performance of the 2.4GHz radios at all so they may as well focus their energy on a sea of IoT devices.

I like the idea of having only one set of wireless networking gear to futz with and optimize instead of having multiples of them. (But I'll probably goof around with Matter-Thread, too, if/when that makes sense to me. I'm by no means done tinkering or learning new things.)

Thanks for the response! Refreshing to hear that it can actually work - I think the main difference between your setup and mine might be that I actually needed the mesh because I had bulbs in behind a couple of steel concrete walls. I installed always-on Zigbee outlets thinking that bulbs would route over those but never actually got around to debugging why they didn't.

Currently I'm also mostly on Tasmota-powered Athom bulbs. They work well, but after not powering them on for longer timeframes (presumably after their internal battery or whatever runs out) they forget my wifi and switch to setup.

After these experiences I'll probably go with dumb bulbs and smart switches/relays for our new apartment. Still keeping an eye on the market and open for recommendations though, mainly because I like being able to control light color through HA.

I think you've nailed the key difference for zigbee, indeed. And I'd love to share some first-hand insight about how Zigbee works with either intermediate repeaters or routers scattered around, but I just don't have any to share.

You did remind me of a thing, though: My Athom bulbs, with ESPHome, do have an annoying mode they drop into when their Home Assistant mothership is unavailable. They still work mostly like dumb light bulbs in this state, but they do a periodic blinky-thing (with a cadence in minutes, not seconds) that is annoying until the HA rig comes back.

But since they're running a copy of ESPHome that I compiled locally, that's almost certainly an ESPHome function that I can hack out/turn off/modify/whatever.

I don't have any direct experience with Tasmota. I remember looking into it with some giddiness several years ago (just because hacking on home electronics does that to me), but by the time it came to start actually buying hardware I decided to go in a different direction.

But I don't recall the Athom bulbs, with ESPHome, ever dropping out and not coming back. Even after the last move where some of them were in a box for weeks: If there was any difficulty, it wasn't something that took a lot of steps to resolve. I think I'd remember if it were challenging in some way.

So I'm lead to wonder what mechanism it is that makes your stuff go goofy with Tasmota.

Inside of these things is just a small power supply, an ESP, some MOSFETs and some LEDs. On-device configuration data is stored in flash right alongside the firmware itself. There's no battery, nor any no real-time clock (if the time is useful, it is set over the network).

Athom does publish steps for switching [some of] their hardware back and forth between Tasmota and ESPHome, if that's ever useful to you: https://github.com/athom-tech/athom-configs

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More broadly, having smart switches and/or dimmers with dumb bulbs does sound appealing. I've got all of the lights in my garage on one smart switch, for instance, and it works well for that environment.

Smart switches would also Grandpa-proof the installation: If a dumb bulb goes out and Grandpa is watching the place, he can just swap it out and things would work fine. (Knowing my own old man, he'd probably use a dusty incandescent bulb that he's had in the glovebox of the car since he stopped to pick it up along the side of an unpaved road somewhere outside of Lincoln Nebraska in 1973...but it'll still work fine.)

But smart switches and relays alike want neutral wires. It's not always straight-forward to integrate them, as I've written extensively about elsewhere here.

And right now, I've got the usual lights in the common areas downstairs set (via the Adaptive Lighting integration) to smoothly adjust their color temperature based on the position of the sun. And I really like that function: I get intense 6000k light during the day that more-or-less emulates the ambient sunlight that comes in through the windows, and a much more serene 3000k light when it's ~dark outside. And nobody has to think about it at all on a day-to-day basis; it Just Works.

This is, quite frankly, pretty glorious to me in ways that I don't think I ever want to give up...so I'm stuck with smart bulbs in lots of places.

I actually didn't try ESPHome yet, thx for mentioning it. That will be my next experiment then. The adaptive lighting also sounds really cool, will try that as well.

Do you know if the Athom bulbs even have some kind of persistent memory that can survive longer timeframes without power?

Yeah, give it a whirl.

There's only two kinds of memory in an Athom bulb: The RAM that is built into the ESP MCU (temporary, fast -- like RAM in a PC), and the flash ROM (permanent, much slower -- like an SSD in a PC).

Data in RAM doesn't survive for even a moment without power. Data in flash should be good for years and years with or without power.

You can run HA in a Docker container and set it to generate backups periodically. If your virtual box (or the host) dies, spinning up a replacement will take up a few minutes, as long as you still have you have a computer capable of running Docker or Podman.

That is no use if my boss says move to different city - there is a lot to deal with in a short time which leaves no time to tear that stuff out. if the house doesn't work for the new owners the courts will make me pay an electrition to make it work.

HA failing is annoying but not nearly as stressful.

I see where you're headed with that now.

It is my intention that when I move, I move my smart home shit with me.

I keep this in mind as I add smartness. All of it can be reversed to normal-house-status in a few hours, at most -- including a trip or two to the hardware store.

It can go back to what it once was almost as soon as "We're showing the house on Thursday" is uttered by anyone.

(The new owners won't want any of it, anyway. Buying someone else's bespoke smart home is like buying someone else's bespoke race car: It may have been a serious investment in time and money as well as a source of tremendous joy for one person at one point, but for the next guy it's just kind of a nuisance.)