Critical listening or a reason to keep tinkering?

If you can let us know what gear you own, we may be more helpful.

I have reached the point where I'm happy with my main equipment, because I can now hear real differences with just about anything I try, and I like what I hear. I may explore adding subs, but that's kinda fading as time passes. The one thing that I do have left, is to upgrade my cables that are twenty years old. BTW - My new mono blocks were the component that made the most difference.
Kenny

Everyone's situation is unique to them. I have optimized every aspect of my system, such as I can afford, without going overboard. I have reached the point where to make worthwhile improvements, a considerable amount of money would need to be spent, money I just don't have, now that I'm retired.

Other necessities come into play, a new roof, heating system, etc. You have to work within your own set of priorities, but, if you're lucky, or careful, you may find exactly what you need before running out of money or WAF.

Good luck on that last one.

Regards,
Dan 

Dan presented a very good and wise perspective that based on genuine experience. Is your goal realistic and emotionally involving music listening experience or is it the quest for "perfect " sound?  This is what must be determined as the pathways are very distinct. If you become obsess with achieving perfect sound you risk the possibility of never being fully satisfied with what you have. In my opinion there is no such thing as perfect sound regardless of how much you spend or how devoted your search may be. 

On the other hand seeking a system that provides pure  listening joy, emotion with an emphasis on your music is very obtainable. You can do this with the realization that "best" component or perfect sound isn't the objective, just deep lisstening satisfaction and appreciation of music you love. Two different routes. My 2 cents worth. 
Charles,  

Spend more on your music library than your system.

Different parts of my system have evolved at different paces and have reached varying degrees of completeness in the sense that you are asking about. For example, over the past 20 years, I went from moderately inexpensive monitor speakers to moderately inexpensive floor standing full range speakers to high end expensive monitors paired with a high end sub to finally a pair of high end expensive floor standing full range speakers.  The loud speakers in my system are now where I want them to be, there is nothing missing, they leave me wanting for nothing more.  Audio happiness!  Ok sure, if I find myself with a winning lotto ticket, I may move up the line in the speaker I have now, but for all practical purposes (even audiophile purposes), there is no reason for me to change my speakers.  I feel that they have reached that sweet spot in my auditory expectations and their place on the diminishing returns price ladder.  I have a similar story and similar feeling with my power conditioner, power cables, phono cartridge, and amplifiers.  There are a few areas of the system where I feel less of this level of completeness.  My speaker and interconnect cables for example, have evolved, but still seem to be holding me back.  I feel the same about my tonearm and to a limited degree (compounded by its technological nature) my DAC.

My suggestion is to try to tap into this feeling of completeness, a philosophical appreciation of what your system does and doesn't do.  If you can get a handle on that, hopefully you will change a component when it needs changing and be satisfied with the components that do so much to bring that sonic smile to your lips. Good luck and enjoy the journey!