[lisper]

The o-rings that require regular attention are the ones that handle high-pressure air. Run-of-the-mill waterproofing o-rings, like the ones used to seal dive watches and dive computers, are fire-and-forget. And yes, dive watches and dive computer have beefier housings than iPhones, but iPhones don't need to be waterproof to 150m.

(I am a certified scuba diver.)

[mynameisvlad]

Dive computers with replaceable batteries 100% have user-serviceable o-rings that need lubing and eventual replacement. My Shearwater came with both grease and 2 replacement o-rings.

HP hoses and o-rings also can and do fail, and, once again, divers are trained to look for signs like the rubber bubbling. There is also not really a difference between the o-rings used in HP and LP hoses and equipment outside the size, and I gave examples of LP hoses failing.

These all require regular maintenance and replacement, and, once again, divers are trained and should be checking their equipment regularly.

But that's all beside the point, which is that your claim is that "[o-rings] are extraordinarily reliable". Except they are not, they require replacing all the time. They may be industry standard, but they are fall from infallible.

[msrenee]

Scuba equipment is most often used in saltwater and is subjected to increased pressure while underwater. The conditions scuba equipment is subjected to vs what waterproof cell phones are rated for are very different.

[lisper]

> need lubing and eventual replacement

Yes. Every couple of years. After being subjected to a lot of pressure cycling.

If you do nothing but take it into the shower or a swimming pool the o-rings will last longer than the batteries.

[msrenee]

Chlorine isn't friendly to o-rings, but I'm not sure where someone would put their phone while in a pool anyways. Mine comes in the tub with me for soaks for sure though.