Carl Chiara, director of brand concepts and special projects for Levi Strauss & Co., is among the growing number of jeans enthusiasts who believe in washing them as little as possible.

Mr. Chiara, who says he wears jeans every day in both work and social situations, believes that "the less people wash their jeans, the better their jeans become. Denim really does shape to people's bodies, and when you wash a jean you lose some of that shape."

He...