“WE need some gray hair” once referred to needing someone with more experience. But I haven’t heard that expression in a very long time.

In fact, many companies are intentionally reducing the average age of their work forces in an effort to save money. Younger employees are generally paid less and have lower health care expenses and retirement costs. As one executive remarked to me recently, “I don’t think anyone really likes this — we all know our own 50-year-old moment will be coming, too.”

There is a surprising downside, however, to encouraging older workers to leave or, at some companies, pushing them out: Less gray hair sharply reduces an organization’s innovation potential, which over the long term can greatly outweigh short-term gains.

The most common image of an innovator is that of a kid developing a great idea in a garage, a dorm room or a makeshift office. This is the story of Mark Zuckerberg of Facebook, Bill Gates of Microsoft, and Steve Jobs and Steve Wozniak of Apple. Last week, Yahoo announced that it had bought a news-reading app developed by Nick D’Aloisio, who is all of 17.