As someone who writes about retirement frequently, I'm well aware that Social Security won't pay me enough money to maintain the sort of lifestyle I know I want. Instead, I'll have to assemble an investment portfolio that continues to generate income for me. And here are three investments I intend to hang onto once retirement rolls around.

1. Dividend stocks

The great thing about dividend stocks is that they allow you to make money in two ways. First, like all stocks, dividend stocks have the potential to gain value over time. You could buy shares of a given dividend-paying company today at $400 apiece, and in 20 years, they could end up being worth $1,200 apiece.

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But dividend stocks also, not shockingly, pay dividends, generally on a quarterly basis. That means getting access to a steady stream of income during retirement, which is particularly appealing to me.

If there's a year when the stock market underperforms and I can't sell stocks at a gain, I can fall back on the dividend payments I receive and use them as income to pay my expenses. And if that's not necessary, I can always reinvest my dividends for added growth.

2. Municipal bonds

Municipal bonds are those issued by states, cities, and other localities (as opposed to corporate bonds, which are issued by corporations). Municipal bonds tend to pay less interest than corporate bonds, but the benefit is that the interest payments you collect won't be taxable at the federal level. Plus, if you buy municipal bonds issued by your home state, you won't pay state or local taxes on that interest income, either.

Here's why that's important to me. Right now, I have my retirement savings in a SEP IRA and solo 401(k). Both accounts give me an up-front tax break on my contributions, but withdrawals during retirement will be subject to taxes. Because of that, it's important for me to have a source of income that doesn't add to my tax burden.

Plus, bonds are generally a less volatile investment than stocks. At during retirement, I feel I'll need to keep a large chunk of my portfolio in bonds to avoid exposing myself to undue risk.

3. S&P 500 index funds

Once I retire, I suspect that my risk tolerance might wane in the context of investing. And that's why I think S&P 500 index funds are a good bet.

Index funds are passively managed funds that aim to match the performance of the benchmarks they're tied to. S&P 500 index funds track an index that's comprised of the 500 largest publicly traded stocks (as measured by market capitalization). The index itself offers instant diversification, which is a good thing to have in your portfolio as a retiree. And that's a great way to keep gaining wealth while getting some protection against market downturns.

The choices you make for your investment portfolio could set the stage for a rewarding retirement. Though I'm not planning to wrap up my career anytime soon, right now, all of these investments seem like a good bet for me, and they may be a good bet for you, too.