Investing is of course an important component of the retirement puzzle, but getting great returns on your portfolio is not enough alone to be well situated for retirement. The mix between three key variables and having the discipline to control these variables is integral in a successful retirement strategy. These three variables are return, risk, and cash flows. Cash flows are not brought up nearly enough in retirement planning, although without intelligent spending the future is bleak. In the article, ”Retirement Investing is all About One Thing” Larry Stein discusses the most important aspect of the variables: discipline. The ability to stay disciplined is integral to being able to retire comfortably and on time.