I didn't know this was an issue with FACE ID with the iPhone X, XR, XS until I experienced and started reading up on it. I was surprised because FACE ID was the new in and improved tech that APPLE boasted about for so long. I love it, and I can't go back to using the fingerprint scanner. So yes, I'm happy they got rid of the fingerprint hardware and use FACE ID now for the iPhone X, XR, XS and all future iPhone models. If the FACE ID brightness trick doesn't work, then you can wait 30 seconds to a minute to use your PASSCODE which is fine but becomes annoying after doing it so many times. I just simply want to pick up my iPhone X, XR, XS and go right into it - with the new models the FACE ID is faster so i'm not waiting as long as I use to - to get into my iPhone X, XR, XS and start texting, calling, or using my APPs. Playing my games mostly, and checking the news. FACE ID on the iPhone X, XR, XS is something that should be one of Apples achievements among-st so many of them.
I'mt thankful for the many achievements Apple has made with the iPhone itself, especially with the newer models: iPhone X, XR, XS. It feels good to be given the future we promised so long ago, and done so beautifully. FACE ID has revolutionized the SMART PHONE industry and whatever apple does with their iPhone every other company follows. It's why 3D touch will be coming out soon for the iPhone X, XR, XS and future models. So not only can you use your FACE ID and Passcode but soon, touching the screen of the iPhone X, XR, XS and future models will allow you to get right in and start using your iPhone. Apple is truly moving ahead with innovation and leaving the resst of the competition behind. Even though FACE ID may not work sometimes and the fix as said above works. It's still an innovating IDEA that works perfectly.
If FACE ID on the iPhone X, XR, XS is and has been giving your issues. Simply ensure the brightness of the screen is turned up, if your in a dark room. If not - make sure the room or area your in is lit brightly so the FACE ID Scanner can scan your features and allow you in. I personally can't wait until the 3D touch comes along with the FACE ID giving you multiple options to get into your iPhone X, XR, XS and future models and start using it right away. FACE ID when it came out was marveled and scrutinized but in the end it turned out to be something - to be hold as being innovating IDEA and one that works, over and over again. The hardware never breaks down and even if your wearing GLASSES, SUN GLASSES, have a beard - etc your still able to get into your iPhone X, XR, XS without issue unless as mentioned above. If your looking for a way to ensure FACE ID works always on the iPhone X, XR, XS and future models just the follow the steps mentioned above and you'll be fine to go.