I have a lot of Zigbee devices, and I've never experienced a pairing issue like this. I use Zigbee2MQTT with Home Assistant, with a electrolama ZZH USB stick - https://electrolama.com/projects/zig-a-zig-ah/

During my first attempt at home automation, I used to mess around with flashing custom firmware onto WiFi devices (Tasmota, ESPHome.) It was a huge pain whenever the hacking process stopped working (tuya-convert), and I had to open up the device, solder some wires, and flash the chip via USB serial.

Nowadays I can just buy any Zigbee product I want (usually from AliExpress), and get it set up in zigbee2mqtt without any extra steps. And it's all local within my home, and no hubs or cloud services required.

I think Zigbee is better for me because I have a lot of battery-powered devices, such as sensors for motion, door contacts, and temperature/humidity. I'm really impressed that the button batteries usually last for 1-2 years.

You haven't had an issue because you are using z2m which tries to support everything. Try using a Philips Hue hub or Aqara or whatever and most devices will not work properly.

That's.... not a long time. The tire pressure sensors in your car have 7-10 year batteries running off the same standard lithium coin cell.

Sure, but it's long enough that I don't get annoyed when I need to change a battery. If I ever build or renovate a house then everything will be wired, but these are working really well for now.

Although you can easily circumvent this with a cheap Zigbee USB controller, Raspberry Pi (or other computer) and something like Zigbee2MQTT. My IKEA bulbs, Xiaomi sensors and Philips remotes all work great as a mesh.

You would think so...

On the other hand, Zwave radio spectrum varies depending on region, so you need to be very careful that you don't spend hours troubleshooting something that doesn't work because it's a device intended for the EU market instead of US.

IIRC, Zigbee is better here.

Yep... cannot use US or EU market (at least I believe that's the case, based on [1] which mentions UK) z-wave gear here in Australia due to incompatible spectrum usage. And the AU market z-wave gear is about twice the price of the US equivalent, since it's low production volume.

[1] https://iot.stackexchange.com/a/2393

I have more zigbee than i do zwave, never had a problem with either pairing to my Nortek USB Hub

Aqara Zigbee devices are renowned for having a longer keepalive check-in period than many routers expect. So when they don’t check in on time, the router marks it as dead. Often, a quick tap of the setup button to re-announce it to its router will cause those routers to “unmark” it as dead—you don’t need to re-pair it. But it’s frustrating enough when it happens.

I have a handful of Aqara sensors that constantly dropped away, so I just flashed an XBee with router firmware and have it on a small USB battery that stays plugged in. That way power outages won’t cause issues with the “leave and rejoin” request that routers will issue to aged-out devices, which my Aqara devices seem to balk at.

I have 8 Aqara sensors (4 temp/pressure, 4 door/window contacts), one temperature sensor consistently has this issues, no others do. Used to be Deconz, now on Zigbee2MQTT with the Conbee 2.