Cons: A retirement portfolio with distinct holdings will require more work to set up and maintain. Moreover, investors who are in charge of maintaining their own portfolio mixes may be more inclined to make adjustments to their programs, and those tweaks won't always be well timed. For example, in the wake of the bear market, many investors bought bond funds, whereas in hindsight it was a wise time to buy stocks. (In fact, many all-in-one funds were rebalancing into stocks during that period.)

If you go this route: Get some professional advice on asset allocation, either from a financial planner or by taking time to learn about asset allocation on your own. And be careful with tactical maneuvers, as even professional money managers have difficulty executing them on an ongoing basis.

Opt for a multi-asset fund or target date fund.

Pros: Convenience. Employing multi-asset funds, whether a static-allocation vehicle or a target-date fund, can help reduce the moving parts in your portfolio. Moreover, target-date funds do the heavy lifting of asset allocation for you. Not only do they set an initial, age-appropriate allocation, but they also manage it on an ongoing basis, making your portfolio more conservative as your goal date nears. Using a set-and-forget-it multi-asset fund can also help ensure that you make changes that are psychologically difficult but helpful to your bottom line--for example, rebalancing.

Cons: Multi-asset funds may be reliant on a subpar lineup of underlying investments, or may at least have a few weak links in their lineups. And as useful as they can be for retirement savers, target-date funds are blunt instruments: They use a single factor--anticipated retirement date--to set their asset allocations. But people retiring in a given year might have wildly different situations that call for different asset allocations: The person retiring in 2020 with a $3 million portfolio almost certainly has different needs than the one retiring in that same year with $250,000.

If you go this route: Be selective. Also, be sure to monitor other accounts you hold in addition to your target-date fund, because the allocations you make there can undermine what's going on in the target-date fund.

Question 2: Will you aim to dampen volatility in your portfolio or will you be more aggressive?

Another consideration when selecting holdings for your portfolio is the level of volatility you're comfortable with. The past 10 years in the equity market--and the 10 years that preceded them--have provided a great laboratory for examining your own behaviors. If you've reacted poorly to market volatility--by selling yourself out of positions when they were in a trough, for example--you may want to tweak your portfolio and its holdings to emphasize downside protection. On the flip side, if you know that you can handle higher volatility if the prospect of higher returns comes along with it, you might consider shading your portfolio toward the aggressive.

If you're aiming for a lower-volatility portfolio: The main way to bring your portfolio's volatility level down is to adjust its asset allocation, but you can also reduce your portfolio's ups and downs by focusing on investments that take a risk-conscious approach to a given asset class.

If you can tolerate more volatility: Have you been positively stoic through the market's gyrations? If so, you may want to tweak your portfolio--both its asset allocation and your investment selections--to put a greater emphasis on investments that have the potential for higher long-term rewards, even though they come with higher volatility. For example, a highly concentrated equity fund, while not for the faint of heart, could serve as a core equity position for your retirement portfolio.

When it comes to selecting investments for your retirement portfolio, I strongly believe that less is more. I'm a big fan of mutual funds and exchange-traded funds that provide broad diversification at a very low cost and require very little in the way of ongoing oversight. From that standpoint, it's hard to beat a portfolio that’s anchored in total market index funds. Retirees might also consider adding an inflation-protected bond fund, since those bonds don't appear in total bond market index funds. Well-managed active funds can serve a valuable role in retiree portfolios, too, especially if the manager pays attention to limiting downside volatility. As always, if you're buying an active fund, be sure to keep a close eye on costs, as high expenses will have a direct negative effect on your returns.