How good is good enough?

For me, "good enough" is when a system covers at least most of the full frequency range, with realistic soundstaging, imaging, dynamics and transparency and no obvious sonic flaws.  When I close my eyes it captures 90% or more of the live-music experience.

At a certain point the quality of the recordings that we enjoy is more of a limitation than our gear or maybe even our listening rooms.  I think a lot of pro recording gear, especially in times past, isn't of as high quality as audiophile gear.

I consider my current system good enough.  It's mainly reading forums like this one that even makes me consider upgrading. 

Good enough is when the last expensive upgrade didn't produce any noticeable improvements.    (Until the next toy comes along)

Many human species are spoiled by civilization and have buried the natural sense of enough. Even successful bank robbers get busted, because they don't turn on that quality sense. 

Good enough for what? Good enough to end my curiosity about what else might be possible - never. Good enough to bring me a lot of listening pleasure in my den - I can pick up everything I need for under $1000 at BestBuy. Good enough that I’d rather have it than not have anything? A pair of headphones for under $20 and my phone.

Curiosity is mostly what keeps me going. I haven’t found a lot of satisfaction in just upping the quality to stratospheric levels on various components. I’ve found more from trying unorthodox listening arrangements and speaker configurations. This kind of experimenting can get expensive, and the creations that don’t work well can’t be taken back, and don’t have much used market value. I consider myself lucky if I can give the stuff away. Fortunately I’ve found that is always the case, so nothing so far has been so bad as to end up at the dump - except for components that I've inadvertently damaged beyond repair.

“that criteria can be settled in advance, with examples marching in afterwards to be judged like contestants in a beauty contest”

The question is not based on an objective reality, but how good enough it is for YOU?

It's not a question of objective (read: intersubjective) reality or how good it is for you. The obstacle to which I'm referring applies equally to the individual. It's about the process of deciding questions of taste, and when criteria are settled in advance the problems manifest -- for groups but also for individuals. Objectivity has nothing to do with the objection.