Wow, does this article get it completely backwards.
This article talks about where your money goes first and then what's left over is what you have to invest, for retirement, non-retirement and for charity.
We constantly get bombarded with the wrong financial messages from the "experts." The priority should be charity (i.e. tithing for many people), investing for retirement and investing in non-retirement accounts.
After you do these 3 things first, then you figure out how much money you have left for your lifestyle. Not the other way around.