Thank you again for the reply. Honestly, hearing from someone who experienced similar behavior with these older UNs is both comforting and kind of messing with my head at the same time 
Part of what made the whole experience so frustrating was that I could never really tell whether:
* my watch actually had something wrong with it,
* whether these movements are just a bit inefficient by nature,
* or whether my expectations were simply too high for an older automatic perpetual calendar.
That’s what drove me crazy about it. On paper, everything always looked “perfect.” Timing was good, amplitude was good, calendar worked properly, etc. Yet somehow in actual daily wear the watch would still slowly lose power over days and eventually stop.
And now hearing:
* that some owners experienced similar things,
* that some people simply manually wind them every few days,
* while others apparently had the issue properly fixed by UN…
it honestly just reopens the whole thing for me.
Part of me wonders whether my particular watch was never truly sorted out mechanically. But another part of me still struggles with the idea that an automatic perpetual from a company like Ulysse Nardin would need regular manual topping-up just to stay running normally under daily wear.
At the same time, despite all the frustration, I still absolutely love the watch and the whole Oechslin concept. That’s probably why I’ve never really gotten over selling it.
The hopeless thing is that part of me almost wants to buy back my original watch. But I’m honestly a little hesitant and uncomfortable to even go down that road, because the person who has it now is more of a watch-friend/dealer type personality, and he’s kind of a shark who might bankrupt me
And beyond that, I think I’m also scared of putting a lot of money back into mine or one of these and ending up mentally stuck in the same cycle again:
* constantly monitoring whether it’s winding properly,
* wondering if it’ll stop overnight,
* debating whether it needs service again,
* comparing one example versus another
I just really want the original one back but I’m afraid to buy it back.
I genuinely appreciate you sharing your experience though. This discussion has honestly been super helpful for me in trying to understand what exactly I was dealing with for those two years.