Here's how I'd try to build a retirement portfolio for the long term. : Investing for retirement is a necessary evil for most people. Certainly, most of us would rather simply spend all of what we earn and ‘live for the moment’. But the reality is that at some point, retirement will come along and an income from a portfolio of investments will be required. Fortunately, retirement is a known quantity in terms of there being the potential to plan for it decades in advance.