Exchange-traded funds offer a convenient way to invest in sectors or niches that interest you. If you expect discretionary spending to grow as the economy finally turns itself around, the Vanguard Consumer Discretionary (NYSE: VCR) ETF could save you a lot of trouble. Instead of trying to figure out which companies will perform best, you can use this ETF to invest in several dozen of them simultaneously.

The basics
ETFs often sport lower expense ratios than their mutual fund cousins. The ETF's expense ratio -- its annual fee -- is an extremely low 0.24%.

This ETF has performed reasonably, having beaten the S&P 500 by about three percentage points over the past five years. As with most investments, of course, we can't expect outstanding performances in every quarter or year. Investors with conviction need to wait for their holdings to deliver.

With a very low turnover rate of 7%, this fund isn't frantically and frequently rejiggering its holdings, as many funds do.

What's in it?
Several of this ETF's components made strong contributions to its performance over the past year. Ford (NYSE: F), for example, advanced about 33%. It's going after rival General Motors (NYSE: GM) with its C-Max hybrid mini-minivan, and expanding in Asia as well. (Nasdaq: PCLN), having almost tripled over the past year, has been boosting its return on invested capital (ROIC) significantly, while its revenue and earnings have grown rapidly. Bears primarily gripe about what they consider Priceline's overvaluation. (But many thought that when the stock was at half its current level.)

Among other activities, Johnson Controls (NYSE: JCI), up about 53% over the past year, makes components for automobiles. It stands to benefit as the global economy finally turns around, and people who have been putting off automobile purchases start buying again.

Other companies didn't add as much to the ETF's returns last year, but could have an effect in the years to come. Lowe's (NYSE: LOW), for instance, gained 21% and is poised to profit from the eventual housing market recovery. (Until then, people are still renovating and repairing their existing properties.)

The big picture
Demand for consumer discretionary products will inevitably recover one of these days. A well-chosen ETF can grant you instant diversification across the industry -- and make investing in and profiting from the sector that much easier.

ETFs can help you find the way to better investing results. To find some great ETF investing ideas, take a look at The Motley Fool's special free report, " 3 ETFs Set to Soar During the Recovery ."

Longtime Fool contributor Selena Maranjian owns shares of Ford Motor, but she holds no other position in any company mentioned. Click here to see her holdings and a short bio. The Motley Fool owns shares of Ford. Motley Fool newsletter services have recommended buying shares of Ford, Lowe's,, and General Motors, as well as writing covered calls on Lowe's. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.