How good is your hearing ? And how do you know ?

I think the OP's question is a bit ambiguous.  One's hearing may be physically impaired due to age, injury or whatever.  But I think the OP means ability to differentiate between a merely good system and a very good system, i.e, one that is capable of producing realistic instrumental timbre, low level information, etc.  As a trained musician and a past recording engineer, I've often wondered what non-musicians were actually listening to when they judged a system.  I don't think you can ever know.  But one thing I learned in my years of working in music - never assume someone else can't hear something just because you can't. IMO.

"So why buy good stuff ?"
It’s all better through a cleaner window.
I don’t need perfect vision to appreciate the majesty of a sunset nor perfect hearing to feel the message in music. I don’t laugh at anyone for not getting this. 

Michael, how can you advocate the old soulful ways when you use digital source as a reference ? You can't make good stuff from s...
In fact, in my experience many if not most people can hear pretty well, as far as I can tell. Yeah, my musician friend sometimes harassed me - can't you hear that ? The hell I couldn't. Hearing should not be perfect but it should be good to be able to "feel the message in music".
So, people here who brag about how great their digital based system sounds are either BSing me or can't hear a thing. It never sounds great, it can sound tolerable - that's all. 

I'm getting older but my hearing is still intact. I can hear a faucet drip on the other side of our house. It's a good thing, because my wife (four years younger) is almost deaf. Am I bragging? Probably, but I have found a way to compensate for these aging ears. Headphones. I have two pair of Stax (009s, and Lambda Pros), and a pair of B&W headphones (for portable listening). Buying a high quality, tube headphone amplifier for the phones isn't cheap, but nowhere near the cost of a megabuck system. It works for me! 

cleeds,

Exactly.  

A thread asking “how good is your hearing?” is certainly a reasonable topic for a thread.  But the OP makes it clear the thread actually wasn’t started with good intentions, but is rather an occasion for inna to insult the hearing of others and have a “laugh” at others expense.  Oh...and if anyone notices this obvious fact it’s “who, little old me? If you think I meant to diss anyone’s hearing  - that’s on you, not him.  

We we should ask members like inna to do better than start baiting threads like this, that start with self-satisfied implied insults.

If this thread takes an informative direction it will be despite the OP.