It’s no surprise that Bret Witke and Diane Rosenstein filled their first home, a 1920s Mediterranean bungalow in the Miracle Mile District of Los Angeles, with mid-century modern designs. They’ve been collecting furniture and accessories of the period since the early ‘80s. Dating roughly from 1945 to 1965, many of these mass-produced but artful pieces reflect the new technologies and materials developed during World War II, from molded plywood and plastics to lightweight and maintenance-free foam rubber and fiberglass. Among the couple’s collection are red-and-white-striped Edward Wormley club chairs, colorful Swedish glass vases, cobalt blue and orange Italian glass light fixtures and a biomorphic American walnut-and-glass coffee table. Witke, 36, and Rosenstein, 37, grew up amid similar modernist furnishings and love the clean lines and diverse designs. Today, they’re as passionate about collecting the classic creations of architects such as Charles Eames and George Nelson as well as those of Wormley and Vladimir Kagan, both of which have enjoyed major revivals recently. “Our generation doesn’t want furniture that’s too precious,” says Rosenstein, who, with Witke opened the Melrose Avenue store Russell Simpson Company (a composite of their middle names) 2 1/2 years ago. “Mid-century furnishings,” she says, “are pieces you can live with.” They’re also highly collectible: The Wormley chairs Rosenstein purchased 12 years ago are now worth 10 times what she paid for them.