<prompt> Human: Im just curious about how, if you have established a number amount for retirement, how did you come up with a number? From a few general internet searches, Ive typically seen recommendations of 70 to 80 of your current annual income level as an estimate for your post-retirement cash needs, multiplied by the number of years you expect to live post-retirement. The rest of the calculations are then based off of that number. But that would make your nest egg goal dependent on which point in time you decided to come up with a number, as income levels will change throughout a career hopefully.Anyway, I know theres no right answer, and everyones situation is different, but I just thought Id get everyones opinion.  <response>: You almost have your answer.Take the amount you want to withdraw each year please, do the math MANY times to be sure this is a safe and sound answer, for the sake of your future. Lets call it XTake X and divide it by 0.04. This is call the Safe withdrawal rate. This will be your nest egg. Why is it called so ? Because your nest egg will be invested.0.04 is effectively 4. Assuming your money is well invested and diversified you should have 4 or more in interests. Thus, you can live off the interests. All bonus interest is reinvested in order to beat inflation for next year. You might want to go for a 0.03 withdrawal rate if youre too anxious about 4.Why would you want to live off of interest gains ? Why not just get the bare minimum and try to break even ? after all, youll be dead, who cares ? Well, Here are a few incentives... Inheritance for your relatives If a medical breakthrough allows you to live an other 10 years, you wont be fucked life expectancy has raised by a significant margin over the last century If you need medical supplies andor complicated, expensive medical care. You get the drill. Think of it as a big, kickass emergency fund.You might or might not need it. But if you do, youll be glad to be prepared. 