The appeal of phone VR is simplicity and affordability: Just use a $100-ish set of goggles and your phone, and you're set. Samsung gummed that up a bit over the last couple of years by requiring slightly different new models of Gear VR to fit its newer phones, most recently the Note 8 last year.

This year, there are a few things any Galaxy S9 or S9 Plus buyer should know before trying to pop it into a VR headset.

Samsung Gear VR: Only use the late 2017 Note 8-compatible model

Samsung's newest phones, the Galaxy S9 and S9 Plus, didn't debut with any new VR hardware. They do work with the Gear VR. However, they only work with the Note 8 model released in September last year, not the nearly identical Galaxy S8 version that debuted in March that same year. We confirmed this with Samsung. The issue is all about the fit.

Apparently, the design of the S9 is different enough that attempting to put it into an earlier S8-compatible Gear VR, released in early 2017, could damage it. Samsung advises using the Note 8 Gear VR, released in September 2017, for the best fit.

How do you know you're getting the correct Gear VR model? The Note 8 version might be referred to as a "Note 8-compatible" model. This guide to Gear VR model numbers could help. (The model number to look for is SR-325.)

I didn't get to try putting the Galaxy S9 or S9 Plus into an older Gear VR headset to test this during my brief hands-on time, but I'd take Samsung's advice and stick with a Note 8 model to try Oculus mobile apps safely, and not screw up your phone.

VR option 2: Google Daydream View works, too

The GS9 and GS9 Plus are also Daydream View-ready. Google's mobile VR platform has a different app store and different library of apps. You'll also need a totally different headset: Google's Daydream View. Luckily, it's easier to fit Android phones into Google's VR goggles, and it'll work with at least the version released last year. Trying it out on the previous Daydream View shouldn't be risky, either, since the headset doesn't physically dock the phone.

The Daydream View ecosystem is more knitted into Android and Google's core apps, and has some apps that are definitely worth checking out. I prefer the Gear VR, but it's nice to have a choice.

Could there be other VR surprises on the horizon?

Samsung hasn't confirmed any changes to VR content when using the new phones, but Qualcomm's new Snapdragon 845 processor inside the Galaxy S9 has lots of optimizations for AR and VR that could promise big changes down the road, including inside-out motion tracking using the phone's cameras, something that Google's standalone Mirage Solo headset does, but the Gear VR doesn't yet.

There's a possibility that Samsung's Gear VR, which exposes the rear cameras, could possibly enable camera-based tracking down the road. Qualcomm's chips support it, and reference designs of future Snapdragon VR headsets are already showing off how it could work.

With Oculus unveiling its own mobile standalone headset, the Oculus Go, sometime this year, and Samsung already having indicated ambitions to make its own standalone VR headset, maybe this downplaying of VR in early 2018 suggests other developments in the works. Or, Samsung is shifting its focus a bit to AR.

Just know that the VR you see right now on a Galaxy S9 won't be the final word on mobile VR this year. 

Samsung Galaxy S9 review: Two steps forward, one step back.

Samsung Galaxy S9 Plus review: The Samsung phone you really want this year.