I make decisions with the goal of being able to answer no to both of those questions. I'm in my mid 40s. I don't always get it right, but I feel the thought exercise is very helpful.
Now, that doesn't mean I haven't experienced mistakes, learned from them, and grown as a person. It's just by the time the latter two happen, I no longer would want to go back in time to change what had originally happened because it's defined me so integrally as a person.
A great example for me is high school, which objectively sucked. At the time, I had a million regrets but over the years, I learned a lot from them and turned parts of my life 180 degrees around in university based on the things I learned in high school. When someone asks me if I would go back and change anything from high school, my reply has been a flat "no" for a few years now.
But alternatively, I fully like my life. Had I taken a different path, I might not have this life. (I might be happy with whatever I wound up with, but I'm happy I'm where I am).
This is exactly what it is. I'm sure that, had things gone differently, it would have all worked out in the end, but life is all about happenstances. If a certain chain of events hadn't happened, I wouldn't have met some of my best friends, or gotten the jobs I've gotten, and I value what I have today tremendously.
If I really think about it, all I have is this moment, right now. The past is just an idea arising in my mind in this moment, and so is the future. Yet, the future I want often depends on making sacrifices in the moment. Clearly, saving all my money and never doing anything fun isn't the answer, and neither is being high on drugs 24/7. The answer to 'living the good life' must be somewhere in the middle, but where exactly? The balance of 'actual experience' (e.g. sitting on a beach getting wasted) vs 'remembered experience' (e.g. hitting up museums and experiencing culture) seems hard to navigate. I feel like I can't really trust my feeling/intuition here, because my brain is bad at correctly predicting what will actually make me happy. There needs to be some principle I can defer to, but I don't know what that would be.
I'm curious how other people navigate these murky waters.