Bonds are not the sexiest subject we could be discussing here this month. Not only are they breathtakingly boring, they are also devilishly complex--a cursed combo if there ever was one.

But since we all need a slice of bonds in our portfolio pie chart, I feel obliged to cover the subject at least once every century or so. To make bonds as palatable as possible for all of us, I asked some sharp financial planners to skip right to the juicy part: what to buy and what not to. Here’s what they advised.

Ignore individual bonds (mostly). Unless you have a lot of money to invest, it’s nearly impossible to create a decently diversified bond portfolio on your own. Joan Parker, a certified financial planner in San Luis Obispo, Calif., says you would need at least 40 different issues to diversify properly, and that’s at $10,000 to $20,000 each. If you don’t happen to have your calculator handy, that comes to $400,000 to $800,000, just for bonds. And because they might be half or so of your portfolio, you’d need liquid assets (not your house, car, or other hard-to-sell stuff) of $800,000 to $1.6 million.

For her clients who can afford such an outlay, Parker sometimes recommends individual municipal bonds, but she tends to avoid individual corporate bonds. The difference, she explains, is that you can buy insured munis, which give you an added layer of protection against default. With corporate bonds, you’re on your own.

If you’re the hands-on type, you can also buy individual U.S. Treasury bonds, notes, and bills through the government’s online Treasury Direct program. Minimums there are more affordable: $1,000 ($25 in the case of savings bonds). For the details, go to www.savingsbonds.gov.

Forget “laddering” unless you need a new hobby. Laddering, you may recall, is an investment technique in which you purchase a series of bonds of varying maturities, such as one to five years. That way you avoid locking in all your money when rates are low, and you always have bonds coming due and cash to reinvest if rates rise. Like just about everybody else who writes about this stuff, I’ve recommended laddering a time or three, but now I’m dissuaded. For one thing, laddering will only complicate your life. For another, we are still talking about individual bonds here, with all their attendant risks. A ladder with a future Enron as one of its steps is going to be a rickety proposition.

Focus on funds. One of the long-touted benefits of mutual funds--wide diversification--may be more important with bonds than it is with stocks simply because individual bonds are more expensive and harder to diversify with. On the flip side, income from bond funds is less predictable and may change month to month as bonds come and go from portfolios. Yet bond funds are also responsive to changes in interest rates, so if rates go up, your income should too, eventually. Buy a typical individual bond and you’re stuck with its rate, for better or worse.

As with stock funds, you will want to spread your bond money across several types of funds. Parker suggests multisector funds that invest in a mix of U.S. corporate and government bonds. She also recommends putting some money into foreign and emerging market funds, which will give you a bit of protection, and maybe some profit, from a falling dollar.

When shopping for a bond fund, look for one with no up-front loads and a low expense ratio (same as with stock funds only more so, since high expenses can really chew into a bond fund’s return). Choose short- and intermediate-term bond funds, not their long-term counterparts. Long-term funds sometimes pay a bit more, but not enough to make up for the greater risk, most experts I’ve talked to say. People buy bonds to reduce volatility in their portfolios, not to increase it,” says Michael J. Garry, a certified financial planner in Newtown, Pa.

Garry recommends bond funds offered by the fee-frugal Vanguard Group or from Dimensional Fund Advisors, which sells its funds through fee-only investment advisers.

Consider ETFs too. Exchange-traded funds are a cross between stocks and index mutual funds. You buy them through a brokerage house, not directly from a fund company. The best of them rival or even beat the scroogiest mutual funds at keeping expenses low, but you will have to pay a brokerage commission, of course.

Whether to opt for mutual funds or ETFs is pretty much a toss-up, says Garry. If you have a discount brokerage account that you consider the hub of your investing empire, ETFs may be the way to go. If that’s the case, he recommends iShares Funds (www.ishares.com), part of Barclays Global Investors, as a good place to start.

However, if you’re more comfortable with traditional low-fee mutual funds, those are fine too. As long as bonds are properly represented in your retirement-planning pie chart, it doesn’t much matter how you slice it.