I don't regret a single upgrade I've made over the years
I don’t regret my upgrades either, but I sure regret all the downgrades I have made. And I made many.
First real stereo was back in 1980 with all Yamaha - receiver, turntable, speakers and tape deck. Cartridge was micro acoustics. That was the entry level of the local stereo store that had higher end stuff that I thought I would never be able to afford (that was true then as a college student).
When I got into stereo equipment more seriously, I was selling systems to fellow students with gear I got from contacts. That was the crazy time when I had severe upgradeitis and went through countless amps and speakers - not as much on turntables. Happily that was only for about a year and I had to focus on graduating.
It wasn't until 15-20 years later that I realized I was doing things backwards - source is the most important, and it goes down the line from there as the signal advances through the system. I didn't really do anything with my system because I couldn't get records anymore. I had to replace my bridged NAD amps because they kept clipping. New amp sounded (B&K) a little better, but I was happy because it worked consistently. Got better speakers (Alons) - better in the bass, but not blown away.
It was not until I got a $500 Music Hall belt drive table to replace my expensive Phase Linear 8000 that finally broke when I had a big aha moment. The sound improvement may have been the biggest jump ever.
Since then I have upgraded the table to 2 Regas (now a P8) with a fantastic van den Hul cartridge I've replaced with the identical one, now going on 10 years. Haven't touched the integrated in 15 years, and finally replaced the 25 year old speakers due to boredom in the pandemic- nice difference, especially with bass. With the time on my hands and the kids finally off the payroll, I have learned a lot about the importance of vibration control/elimination isolation of components, especially the turntable mainly from posters on Audiogon, so thanks. I wouldn't say aha, but definitely noticeable, which at this point, takes some doing (and $$) to experience. These were not inexpensive, but worthwhile and probably less that upgrading a component or two.
I wouldn't mind reliving the experience in college of first appreciating music and building my record collection and spending every cent I had on it, but it would have been infinitely better if I had my present system back then. I am now at a very content level where I most likely will stand pat unless something breaks or I decide to experiment with a cartridge change at the next stylus wear out crisis. Or maybe if I win the lottery, which is unlikely since I don't play. Otherwise, plunking down $30-$40K for another aha moment (that may not be that revelatory) doesn't appeal to me.
Somewhere around 1966 we and a friend went into a store call the "Ear Drum" off Imperial Highway in Hawthorne CA. The store was very dark with the equipment illuminated on shelves. A salesman yelled at us "Hey you kids get out of here", another voice said "Let them stay, they just may be future customers" They told us look but don't touch. For me, at that age the room was amazing, the gear glowing in the dim light. The lit tubes and the area lights on the face plates are a wonderful memory. My system has 26 tubes.
Back in the day when I barely had two cents to rub together, I scratched my hifi itch via hifi rags like stereophile et al. My "virtual" systems favored components from Nad and Adcom. I loved the clean looks and low profile of most of their gear. I also liked Carver's stuff.
I'm still influenced somewhat from those early years. I still favor diminutive components with clean looks. Sound is a major factor in the now that didn't come into play with my former "virtual" systems. I still like the looks of the classic Nad/Adcom/Carver components but from a performance perspective they don't fill today's needs.
1973 Sony Str 7065,Bose 901s I got used with stands and custom made based that lifted the speakers to ear level sitting down..receiver was $350 ,Bose 901 used 2 old $315,turntable was a Technics SL 1300 with Shure 100 cart that was $350 also.Now I own Caryin 50 tube in amp $1000 ,Nad 588 tt with blue ofton cart.$900,Emovtive cr3 cd player $300.Oh speakers are Polk Lsim 707 returns ,got them for $1100 a steal.I loved my 70s unit as I do my 2021 system.But always buying vintage stuff.