I've thought about this a bit with regard to savings in tax-advantaged accounts; basically my reasoning is that there's no reason for me to lock up money for tax deductions if I will never need it or spend it. My rough estimate is that I'll be very safe if I have $1,000,000 in current dollars when I'm 65. Assuming a 4% real rate of return, and given that I'm 29, that means if I had $244,000 in such accounts today (I don't) I would not need to add any more. Obviously, if market returns are lower than I expect, I could add more later as needed.
I understand Roth conversion and of course the reasoning that's like, why not make sure you have as much money as possible when you're old, but once retirement is secure I don't mind paying higher taxes in exchange for having more money in the present.
It's also not a question that will be relevant for quite some time since in reality I only have like 30k in tax-protected accounts. But in 10 or 20 years I could easily be like "well the amount of money is 'plenty' so I'm not even gonna worry about it." No reason to pre-fund the pension plan out to 500 years.