What is your experience with the law of diminishing returns ?

When I first started upgrading, I could hear the difference.  However, I couldn't always tell if the upgrade was an improvement, just different.  Eventually I learned.

I hit diminishing returns when I couldn't hear a difference after an upgrade.  But there was still a  cumulative effect from multiple upgrades -- like I couldn't hear differences each time when upgrading amp, preamp, and cables, but after all three upgrades, I could hear the sound was better.

So I kept upgrading until I got to a level where my ears/brain had stopped learning and I really couldn't tell any more.

You guys gotta check it out. Low mass inexpensive systems are where it’s at. No more house AC, AC ground, no more speakers, speaker cables, amplifiers, preamps, interconnects, digital cables, fuses, no more transformers. No more distortion. No more noise. No more pencils, no more books, no more teacher’s dirty looks. 🧐

So there it was...

A different perspective...
Twenty years ago, when I had better ears and a less expensive audio system, I made a visit to the local high-end store. I had $5k invested in used equipment (ARC tubes, Soundlab Dynastats, HGS sub). Listened to my reference music on an $80k new system (Martin Login top of the line bi-amped with four Krell monster mono amps, etc.).

The higher end system definitely sounded a lot better. The 3D soundstage really stuck in my mind. After an hour of listening I walked out of the store with a big grin on my face thinking I didn't really hear $75k of difference.