My hub arrives tomorrow. I've decided to do it all in one day. Exclude from ST, and then re-include into Hubitat.
Now, despite having all the manuals for each device I already KNOW some devices will be impossible to exclude from ST. For these, can I try excluding them from Hubitat to see if that clears them? Or, is there any problem with trying to pair devices that haven't been excluded from ST first?
I have about 100 devices. Gonna be a long day.
If your devices are Zigbee, you don't need to do anything with SmartThings. Those devices will have a reset button (typically you depress it while inserting the battery, but it may vary) that will undo their association with ST and leave them ready to join Hubitat.
For Z-Wave, some devices may have a hardware based reset built into them (it appears that Z-Wave Plus devices are required to have this on every device with the Z-Wave Plus logo; older devices may require exclusion from a hub or they may have a device reset capability built into them as well ). Hubitat can do the Z-Wave exclusion from the Z-Wave settings page, so you don't need to do it from the device or SmartThings unless your device is out of range of Hubitat's Z-Wave radio.
So technically I don't need to do ANY exclusion at the device itself if I can do it within Hubitat settings? Or only for older Zwave devices?
Every Z-Wave device, old and new, can be excluded from Hubitat (assuming it is in radio range). Some Z-Wave devices can do a factory reset without any hub; not all have this capability. So you don't really need SmartThings, but it might make sense to do it there if your devices depend on repeaters to get to the hub (you can dismantle your mesh from the farthest points and work your way in to the closest from the hub).
When you rebuild your mesh, note that not all Z-Wave devices can join through a repeater. Some of the oldest ones need to be within radio range of the hub. More recent Z-Wave devices (those that support Network Wide Inclusion) and Z-Wave Plus devices can join the mesh through repeaters that also support NWI (these would be AC powered Z-Wave devices with NWI). So if you have issues joining the network, move the device closer to the Hubitat (or vice-versa)-- and then do a Z-Wave repair, or the Hub won't be able to work with them when they are in their final locations.
Just a heads up, going nuts and trying to do all this in one day may not be the best route. There are some faqs in the community you may want to read up on before you settle on this path.
You need to reset or exclude every ZWave device before it will join Hubitat. Any ZWave controller can perform the exclude. You can certainly use ST, you can also use Hubitat or even a Minimote. My favorite is the Aeon Z-Stick. and I've joked a couple of times now that I could just put the Z-Stick in Exclude mode, hide it in my pocket, and walk around your house turning things on and off and clear the whole house for ya. 
Is that a Z-stick in your pocket or are you just excited to... deconstruct my mesh?
But yeah, I'm looking at the HE/ST Integration and/or OtherHub. Obviously I've never even held a Hubitat in my hand or seen the dashboard, so I only have a vague idea.
Ideally I could exclude everything in a day and then re-pair and translate my pistons to Rule Machine. But I have occasionally spent upwards of 30 minutes trying to get a single device to pair, so...
And then there's hunting for the right device handler and making whatever groovy changes need to be made. So you just may be right, @mike.maxwell
The reward is well worth the effort
I'd plan it a room at a time, making sure to NOT isolate devices that were using that room as it's mesh.
If you can take the down time of Excluding everything, turning off ST and then starting over with Hubitat, wow, that would be cool. 
I shudder at the thought. But honestly I could totally handle that. And it might go faster since I've learned most of the weird quirks of these things the hard way. But we'll see...
I found that using general exclusion mode via the ST Hub was more successful than using the Hubitat hub for my old GE Z-Wave light switches. YMMV.
@ogiewon - you may remember that Hubitat did at least two updates to improve their Exclude. Live Logging was one if my memory is accurate.
One thing I remember from my Z-Wave decommissioning on ST (and also, a couple of times on HE) when doing excludes was that a few times there was no message produced by the ST app when in fact the exclude did happen correctly. I made a habit of trying the exclude, then if I saw no results, try operating the device from the ST app. If it wasn't able to operate it, then the exclude worked. Seems like all my GE switch exclusions went down this way.
I tried this out yesterday excluding 4 Z-Wave devices and it was pretty good but I still prefer ST because the app pops up a notification for successful exclusion instead of looking at the live log and look for the message. If you don't have ST then nothing wrong using HE for exclusion.
I was having a hard time adding a couple of devices and find success with after a hub reboot or Z-Wave repair so don't kill yourself spending too much time adding and get frustrated on a device.
I actually have a digital folder with manuals for all my devices. Yeah weird but saved me plenty of time searching around.
I like my Aeon Z-Stick.. blinking blue or orange light (include or exclude) with flickering when actively performing. Battery operated, meaning portable.
I actually have a digital folder with manuals for all my devices. Yeah weird but saved me plenty of time searching around.
No that's a great idea. Some of these exclude routines are not intuitive. "Hit reset twice while holding power button, inserting batteries, doing a backflip, and humming the national anthem"
I did the same last Saturday. New Hubitat just staring at me, daring me to "git 'r done" and I didn't want to manage multiple systems. I decided the band-aid approach was best for me, "grip it and rip it" (aka the "Tin Cup" approach).
Steps I lined out:
I don't have 100 devices, but it still took some time and LOTS of patience (exclusion/discovery process isn't always as smooth as you'd hope). In the end, it was a very therapeutic process for me and I'm very happy I have everything up and running in Hubitat!
Sounds like a plan. I also realized I should probably take screenshots of my more complicated pistons. Once I start excluding devices I won't be able to tell what was in there.
I'm revisiting using a minimote for exclusion/inclusion. I didn't have luck last time, but was probably doing it wrong. This looks to be updated: FAQ: Use Aeon Minimote for Inclusion - FAQ - SmartThings Community
You know what would be great? TWO minimotes. One on ST for exclusion, and one on HE for inclusion.
Exclusion is "universal"
ANY device that can initiate exclusion can exclude ANY device.
The Minimote, paired to Hubitat, will trivially exclude devices that are paired to ANYTHING, including ST.
So you have your Two Minimotes.. all in one cute white package 
{ I'm not saying exclude/include is trivial, just that entering the mode(s) is. ]
aHA. And on the flipside, inclusion should be one-way? (only needed one-way in this case)
Okay, and now I get your Z-stick joke. Wow, that's devious.
Download the Hubitat app
