Hi everyone
I tried the original Xiaomi Aqara contact sensors I had from my move from SmartThings but they would never stay connected to hubitat.
I then brought Sonoff SNZB-04 and again they dropped off, the max I get is a few weeks, Strangely I have one button that has stayed connected for months.
I have around 8 SmartThings power outlets around the house
Has anyone tried anything else that is true ZigBee 3.0 and doesn't break the bank?
These work with Hubitat:
https://www.amazon.com/THIRDREALITY-Contact-Security-Required-SmartThings/dp/B08R9PH4JT/
https://www.amazon.com/Linkind-Zigbee-White-Security-Automation-Required/dp/B07YDF7967/
The Sonoffs should work as well. I suspect something isn't right with your SmartThings power outlets.
Not sure you realize I'm from the UK
My outlets were all replaced by Samsung due to the dodgy pin connection that could cause the outlets to melt/burn but they are not the 2019 version.
If you can find those Zigbee contact sensors available in the UK, they will work on your system. Sengled contact sensors should work as well (again, if available to you).
Other UK-ers will hopefully drop by w/more advice.
Truth be told I assumed a Maple Leafs fan would be from Canada 
Anyway, Linkind sensors are available in the UK. Frient zigbee sensors also work with Hubitat.
OMG, those people are everywhere! A friend of mine here in SoCal will not shut up about them.... 
Can't be helped watched a random game like 18 years ago back when the UK only got one game per week, Leafs vs Red Wings and of course leafs played well and won the game I then continue a life of pain supporting them while the Red Wings win multiple cups.
Another note I couldn't cope with one random game a week and back then no streaming services existed I set up a torrent website it got pretty big The Sports Torrent Network closes after police warning - BBC News
Wow...that is being a fan on a whole new level...most people don't almost go to jail for their team! 
(Other than the really dumb bombed-out drunken ones, I mean.) 
I'm using a couple of the Sonoff ones using the 'system' 'Sonoff Zigbee Contact Sensor' and the are rock solid.
For repeaters I'm using Salus, Xenon, Ikea and these.
I also have a couple of Aqara/Xiaomi and a few Iris 3320-L contact sensors.
It has been mentioned elsewhere that the Sonoff devices can have 'flakey' battery connections and some people, including me, have put more tension in the contacts and packed a piece of paper under the cover to give a nice tight battery fit.
BTW, I assumed you were in Canada too.
I wanted out anyway as it was getting too big it was originally just ice hockey but moderators and cappers wanted to do other sports, Last few years of the site I didn't even need it as NHL.tv started streaming all the games for £100 a year was available.
When I got the email got it confirmed by TorrentFreak UK Police Force Shutdown of Sports Torrent Network * TorrentFreak it was a legit email as there were terrible mistakes in the email the email also arrived in my spam folder. Once confirmed I refunded donations for the last 2/3 months and shutdown the website.
I miss the moderators, I even met one in person at a NFL game in London he was from Germany.
Cheers for the tip
They look huge but found them at £19.99 each and they take two AAA batteries they should last forever
they seem great value if I could find them in stock will keep looking
I have over 15 of these door/window sensors, rock solid. Takes 2-3 weeks from China but worth the wait.
I would suggest the Aqara contact sensors: they are stable, small e cheap. The battery lasts forever - Mine two older are connected to Hubitat there is more than two years, and their batteries are around 50%!
I have a huge bag of Original XIAOMI AQARA sensors not only were they a bitch to pair to ST or Hubitat they never stayed connected to Hubitat, worked fine with ST except once when they all dropped off
Can I ask what zigbee channel you are using and also your 2.4Ghz channel on your wifi router. You are probably aware but these can clash and cause zigbee issues.
The third variable to add to @bobbles points is the brand/model of the zigbee repeaters in the mesh. The Aqara sensors are super-finicky about which repeaters they'll use stably.
WiFi AP 1 Channel Wifi 4
WiFi AP 2 Channel Wifi 13
WiFi AP 3 Channel Wifi 6
Hue 1 Channel Zigbee 11
Hue 2 Channel Zigbee 25
Hubitat Channel Zigbee 15
I have no issues with any other devices connected
All my ZigBee repeaters are V2 of the original UK outlet
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