John C. Bogle, who died on Wednesday, is widely seen as having changed how ordinary people invest their money. His firm, the Vanguard Group of Investment Companies, which grew to have $4.9 trillion under management, was built on a belief that, over the long term, most investment managers cannot outperform the broad stock market averages.

“Jack Bogle made an impact on not only the entire investment industry, but more importantly, on the lives of countless individuals saving for their futures or their children’s futures,” Tim Buckley, Vanguard’s chief executive, said in a statement.

Here are some of Mr. Bogle’s investment tips:

1. Stay the course

“Wise investors won’t try to outsmart the market,” he says. “They’ll buy index funds for the long term, and they’ll diversify.”

Long-term investors must hold stocks even though the market is risky, because they are still likely to produce better returns than the alternatives, Mr. Bogle said in 2012.

Investors should weather any storms, he told The Wall Street Journal in 2016.

“If we’re going to have lower returns, well, the worst thing you can do is reach for more yield. You just have to save more.”