I had this done a few years ago [0] and the article is pretty much spot-on. Especially about the process - the audiologist will insert a tiny cotton ball allll the way down in your ear, then squirt the polymer in (which is creepy feeling). You wait for it to cure, and they pull it out & trim any excess.
Note that you can now get custom sleeves which slip over commercial earbuds like the Apple AirPods, so you can get a perfect fit and they're less likely to fall out. You get to choose your color. I went with different colors for the right & left ears, to make telling them apart easier.
They are noise isolating, so you will have to pay attention to your surroundings (traffic, people approaching you from behind, a coworker trying to get your attention). But they don't block enough sound to make them effective at loud concerts or at a shooting range. Wear proper hearing protection for those events.
Speaking of which - watch your volume levels. It's super easy to play them too loud and damage your hearing. Take breaks every 30-40 minutes.
I used them with a set of Shure SE315 earbuds. I mentioned the Apple ones because that's what many people have today and are similar in price.
The fit on mine from custom insert to the Shures was pretty tight (good for air sealing). I could have drilled the holes a little larger, but it was easier to just warm them up with a hairdryer.
Note that you can now get custom sleeves which slip over commercial earbuds like the Apple AirPods, so you can get a perfect fit and they're less likely to fall out. You get to choose your color. I went with different colors for the right & left ears, to make telling them apart easier.
They are noise isolating, so you will have to pay attention to your surroundings (traffic, people approaching you from behind, a coworker trying to get your attention). But they don't block enough sound to make them effective at loud concerts or at a shooting range. Wear proper hearing protection for those events.
Speaking of which - watch your volume levels. It's super easy to play them too loud and damage your hearing. Take breaks every 30-40 minutes.
[0] Many thanks to RK Audiology in Austin. https://rkaudiology.com/custom-fit/