By the time your reach retirement age you should have saved enough to last you the rest of your life, so that effectively any additional income can be spent completely.
> You cannot save 100% of your pre-tax salary
Depends on the industry in which you earn your salary. Some are not above the board.
Interesting. Which industries in particular?
Illegal ones
And where you work. I've had Dubai-based companies try to sell me on "work here, pay zero taxes". (I politely told him I cared more about human rights.)