This is an interesting question. I am firmly in the not-changing-for-a-very-long time camp but when I think about it that has two main reasons. First I got a family and did other things for many years which meant I did not have as much time nor money to think about hifi upgrades. Now I have some more funds but not enough to upgrade everything over and over. Maybe I would be a real flipper if I had the funds?
I am in the process of planning my next upgrade which I hope will happen within a year or so. I might upgrade two parts of the system. One hard question my wife asked was "if you do this upgrade now for $X, are you then done?". And even though I have upgraded very few things the last years I don't really like to decide now that I will be done. Of course I could live with that for years but if I have the financial means it may be interesting to upgrade something or everything again within the next 5 years or so.
As for who is best to listen to, there is a downside of listening to me or anyone else like me, I have not had that much gear going through my home. I have mostly heard new things at a dealer or at audio shows. I think you will hear more nuances when you have a piece of gear at home and can listen for days or weeks to it. If I were to recommend a dac right now it would be from dacs I heard at dealers or shows or from what I've read. Or, a very, very old dac which I don't think is of much interest for you.
So I do pay attention to what some "flippers" say also. I do add a grain of salt to some things or try to interpret what they say and think about if that thing they did not like as much as their new gear could still suit me. If someone says that their new $10k dac is much better than their old $5k dac I think it is interesting but I still don't have a $10k budget for a dac (right now) and if they say that they have tried three $5k dacs at home and choose the last one it may still be interesting to hear what they liked or did not like with the other dacs.