A million dollars a year is 2740 a day. If it is spread out over 40 years, it is saving 70 dollars/day. This is 25,550 a year. Add in compounding, this is difficult but doable.

A billion dollars a year is 2740000 a day. If it is spread out over 40 years, it is saving 70000/day. If spread out over 60 years, it is 46,000 $s/day. It is safe to say that this is beyond the reach of most people.

Now, let us look at the first paragraph - average GDP in USA is 58K dollars, ( or 158 dollars/day) so saving 20% over 30 years with 6% return will get one there.

cheers!