Heya! One of the authors here.

Nope, its a one time thing. When the feature is enabled, a flag is set on the iCloud account, so you can travel anywhere and have it work. At the same time, a EQ profile is pushed to the transparency mode of the Airpods, enabling the hearing aid features.

Once done, it sticks with the Airpods, unless you reset them.

However, an interesting quirk is that if you enable this on someone's airpods, and _their_ device/account does not have it 'available', they wont be able to tweak the settings on their device.

Very cool, glad it sticks.

I live in India and I have been using hearing aid feature since at least March when I bought Airpods Pro. Only that it wasn’t called as such earlier. It uses the audiogram I had provided it which it used to create a customized equalizer for my hearing disability. I am sure they must have improved upon the capability in new OS versions but functionally it has been present for a while now.

I suppose the difference is 1st party support for creating the audiogram, plus the clearance from the US gov to market it the way they want as OTC hearing aids

It also applied the same profile to both ears, which matters for some. My hearing loss is highly asymmetric.

Does it still do that? I understand it had problems with asymetric hearing loss earlier.

Still did it on 18.0. It just averaged the two ears into a single profile.

I wonder if the flag gets reset every so often if the device doesn't think it's in the US for a long period of time. I've heard Apple considered that for some of the other EU restrictions

Probably not to account for people spending lots of time outside the US. The main restriction is not selling items with particular features outside of approved countries but them getting used after being bought elsewhere isn't usually a big deal. India doesn't care about my Grandma wearing her hearing aids because they're not approved in India and if the government doesn't care where's the incentive for Apple to break functionality for customers?