-If you aren't old and you ain't working, you are probably spending. I know I do.
-How much to budget for personal healthcare, including obtaining insurance?
-How long you plan to live?
-How much do you want to spend?
-How much you want to leave to heirs?
-
How much risk that you want to take that financial markets won't do anything worse than they have in the last 100 years?
-How much of a cushion you want, just in case?
-How prudently you allocate your assets?
-Political risk of confiscatory, redistributionist tax policy? A lot can happen over a few decades.
-Natural disaster that wipes you out and being underinsured?
-Increased unanticipated need or desire to support loved ones?
There are plenty of black box financial calculators that will spew out lots of precise, but not necessarily accurate data.
Short version, what you are looking at is what is known as a "sustainable withdrawal rate" Assuming that you have a reasonably prudent portfolio and financial markets don't throw us anything worse than the great depression, political risks don't show up, you are bullet proof with a 2% withdrawal rate, very probably safe at 3%, probably OK at 4%. Allows for inflating contributions.
Anything more than that you are taking some risk of running out of money. Interestingly, assuming that the future is not that different from the past, there is not that much difference statistically in financial retirement risk of running out of money living 30 years vs living forever.
- 2% 10 million= $200K
- 3% 10 million= $300K
- 4% 10 million= $400K
Roll the dice.