That is a subjective question.
Lifestyle expectations, longevity expectations. Single? Married?
Medical issues, hereditary medical issues.
Retiring is not just about wealth but income too. A starting point would be how much you think you would need to live on each year then times that by 20 or 25 to get a 4 or 5 percent draw down per year and have most if not all the capital left to leave to heirs.
Eg 5% drawdown on $1.6m would be $80k a year. Just because you take $80k does not mean you have to spend it all each year either.
