When Tamara Houston's daughter developed a painful eye condition - on a Sunday, during a high school rodeo competition - the Yuba City mom ... picked up her cellphone and called her family's primary care doctor, who met them two hours later at his Rocklin office. The cost of the weekend emergency visit? Zero, because it was already included in her family's monthly $200 fee. Houston's family of four is taking advantage of concierge medicine, a small but growing trend. Under a concierge-style practice, patients pay a monthly or annual fee ... in exchange for longer appointment times, same-day visits and round-the-clock access to their doctor by cellphone, text or email. Some concierge doctors even make house calls. I would never go back to a regular practice," said Houston. "This takes all of the bureaucracy out of the equation. I don't have to deal with co-pays or insurance. And we get to see a doctor who knows us." Concierge medicine ... has gained more traction in recent years among both physicians and patients. "Mainstream medicine doesn't allow you to practice good medicine," said Dr. Chris Campbell, [the Houston family's primary care doctor]. In his old practice, the constant churn of patients "felt like assembly-line medicine." Dr. Marcy Zwelling, an internal medicine doctor in Los Alamitos, switched her practice nearly 15 years ago. "We've arranged for good, cash prices so patients can get their care and understand the value of what they're buying," she said. "It's huge. And it's absolutely cheaper."