First off, every financial calculation must adjust the after-tax income for the cost of living (especially housing) of wherever the job home is vs. some reference (e.g., a place out in the sticks where the land value is basically zero, or at least some minimum that you would be satisfied with). Next is that there should be some baseline spending amount that you feel is worth working to earn - i.e., anything over this would be "I don't care for the utility of the spending if I have to work extra for" - and earning over this amount would mean that you spend that same baseline amount but sock away the excess. Then finally, there is the point of "critical mass", where you are financially secure at that desired baseline amount of spending forever (or until some age when you figure extra money wouldn't matter); once you hit that point, you should retire.