Personally, I am pretty happy with my present system and actually am honing down on the number of amplifiers I have, settling on potentially three that I enjoy a little more than the others for a few reasons. I recently tried a set of rather expensive interconnects and speaker cables (for me at least !) that had a generous 60-day return policy. While these cables did have some slight but noticeable improvements in the micro-detail and sound stage, they weren't enough in my opinion to keep them over my present cables as they were over 3X the price. And that was after over 700-hours of painstaking break-in. I think getting to that "law of diminishing returns" point, this will be a moving target for each of us audiophiles based on discretionary income and our perception of the value difference between what we presently have and the new one. Also in play is the actual value of the old one recouping some of the $$$ for the difference. And we can't throw out the "emotional" part of the equation either ! Now... Would I have enjoyed the auditioned cables more than my present cables ? Yes. However I'd much rather save my $$$ for another potential tweak or upgrade than this one. In fact, I've just completed auditioning and purchasing another set of interconnects/speaker cables competitively priced also with a generous return policy to the previous ones as they did a number of things noticeably better. Many of us are pretty satisfied with our systems, however as time and funds avail, I know I am always interested in tweaks to improve the music experience. Just not in spending a lot to get there !
"Diminishing Returns"
I have a relatively simple system in my smaller room. My system is made up of older gear. My system consists of: a phenomenal pair of Revel Salon 2 speakers, Hegel H590 integrated amp, Ayre Acoustics QX-5 Twenty Streaming DAC, Roon Nucleus Plus music server, Audioquest Niagara 3000 conditioner, Audioquest & ATC power cables, JPS Labs speakers cables, Audioquest XLR interconnects, Shunyata Research ethernet cables, and an assortment of tweeks throughout my system. I get to hear all kinds of great sounding gear in all price ranges at my local dealers and also at the audio shows I attend every year. It’s nothing for todays manufactures to ask 30K, 40K, 100K for a pair of stand mount, bookshelf speakers. There’s such a wonderful, beautiful sea of great gears out there for audiophiles to choose from. However, the sound quality of my relatively simple audio system is so incredibly compelling and so incredibly satisfying and provides me with such a high level of musical bliss in my room, I just don’t have a desire to spend more. I’m sure there’s others out there who feel the same about their speakers/system.