Investors can find plenty of great exchange-traded funds (ETFs) to generate income. Which Vanguard ETFs offer the highest dividend yields? The SEC yield, by the way, is a metric developed by the SEC to help investors compare funds.

When I was running marathons I would remind myself (somewhere around mile 20) that if it were easy to run 26.2 miles everyone would do it. But everyone doesn't run marathons because it is very, very hard.

Its smart to seek income from your investments -- whether it's because you need that income to support yourself in retirement, or whether you want to use it to invest in more stocks. It's also a fine idea to seek that passive income from exchange-traded funds (ETFs) that are focused on dividend-paying shares.