As my wife and I — and millions of other first-wave baby boomers — begin thinking seriously about income in our post-working years (and may those working years continue for years and years to come), an idea that has been floating around in my mind for a while finally has crystallized.

Simply, I've come to believe that successful retirement is a matter of saving enough and not spending too much, rather than being a function of successful investing.

Now here comes the heretical part, especially after years of writing about investments and earning a living based, indirectly, on the sales of investment products: the investment part really isn't all that important.

Recent research from Thornburg Investment Management Inc. of Santa Fe, N.M., found that among major asset classes, only common stocks and municipal bonds earned a net positive return after expenses, taxes and inflation over 30 years. But over other time periods, such as five and 10 years, for instance, only government bonds produced real returns.

Does that mean that we should give up on investing? No. But after years of hearing about asset allocation and risk tolerance, non-correlated assets, alternative investments and buy-and-hold versus trading — all interesting and important to some degree — I think that for most people, most of the time, all that stuff is academic and perhaps largely irrelevant.

Evan Cooper opinion InvestmentNews.com