The one thing that everyone should know is, “Planning is essential, but no plan survives the first serious problem.” Apologies to General Eisenhower and probably a bunch of other people. I read a lot in the retirement literature. Been trying to convince her for decades to buy a retirement home. Me, “You don’t have to live there. It just needs to be somewhere other people will want to live.” She, “It’s too risky and too much trouble.”
Life is about trade-offs. Not making a decision because you refuse to embrace this concept is still making a decision—and probably not a good one. My wife likes to constrain most problems so that there’s no possible solution.
The second thing is to learn the details.
For example, taxes are a big effect on your cost of living. Learn about them! Healthcare is an issue. Great healthcare is largely useless if you can’t find a good doctor who’s accepting new patients. Almost every time that I learn new details, the “optimal” retirement landscape changes. For example, I want to leave money—if any is left when I die—to my nieces and nephews. A few states tax such bequests outside of their normal estate taxes. I won’t live in any of them.
Third. Experiment before you commit.
My wife hasn’t retired yet. I’m semi-retired. We don’t need the money from employment—not my wife’s opinion, but mine—so I won’t take a job that’s not fun, or at least mentally challenging.