Want $1 Million in Retirement? 3 Simple Index Funds -- and 12 Sector ETFs -- to Buy and Hold for Decades.

If you're saving and investing for retirement and you want to do well -- without having to become a stock market expert and top-notch stock analyst -- look to simple index funds. An index fund tracks a particular index, such as the S&P 500 index of 500 of America's biggest companies. It holds all or mostly all of the same components, in roughly the same proportion. Thus, it aims to deliver roughly the same performance -- less its fees. And the best index funds tend to have ultra-low fees. Hooray, right?

Here's a look at three simple index funds you might consider for berths in your portfolio. Note that each is an exchange-traded fund (ETF) -- a fund that trades like a stock. ETFs have grown quite popular and are easy to invest in via any good brokerage. After them, I'll offer a host of sector funds for your consideration.

Image source: Getty Images.

The simplest and broadest index funds

If you want to spend the least time thinking about your portfolio, you might want to just stick with one or more very broad index funds, such as the ones below:

Source: Morningstar.com.

The Vanguard S&P 500 ETF can be all you need. The 500 companies in it together make up about 80% of the total U.S. stock market's value. Its low, low expense ratio (annual fee) of 0.03% means you'll pay just $3 per year for each $10,000 you have invested in the fund.

The Vanguard Total Stock Market ETF has the same low fee and includes just about all of the U.S. stock market, including many small-cap and mid-cap companies that don't make it into the S&P 500.

The Vanguard Total World Stock ETF goes even wider, encompassing most of the world's stocks. It's perfect if you're bullish not only on the U.S. economy but also the world's -- or if you want a more geographically diversified portfolio.

Invest in one or more of these three, keep adding meaningful sums regularly, and you can build a hefty nest egg. Given that the stock market has averaged annual returns of close to 10% over many decades, the table below shows how your money might grow at a more conservative 8%. (Over your investing period, of course, you might average more or less than 8%.)

Source: Calculations by author.

You can see that you can amass $1 million or more just by regularly plunking certain sums into the stock market over a long period.

Sector index funds to consider

Of course, you might want to keep some of your assets in funds that might grow more briskly. For that, you might focus on some impressive growth-oriented ETFs.

Or, instead, focus on sectors or niches that you're very bullish about. Below are some top sector ETFs you might consider:

Source: Morningstar.com.

If you're like me, your eyes will go right to the top for the fattest returns. But remember that these are past returns, and the coming years might deliver different performances. Think about which sectors seem most promising to you. In the coming years, do you foresee lots of homebuilding in the U.S.? Do you expect semiconductors to remain in great demand? Do you perhaps expect a recession, in which case you might want more steady utility and consumer staples companies in your portfolio, delivering reliable dividends?

Think about what kinds of investments will best suit your risk tolerance and investment goals. Remember that a high average annual return might be due to a single outsized year -- and that a relatively low dividend yield might be growing faster than a higher one. Basically, look more closely into measures that matter to you.

However you go about it, be sure to save and invest for your future -- and to have a solid retirement plan in place. Whether with these ETFs or individual stocks or other investments, you may be able to amass $1 million or more by retirement.