It’s the same routine every year. Cash registers at area gyms get a workout in winter before the surge of new members dwindles in the spring.But local fitness centers and instructors are working to make the healthy lifestyles stick year round.The seemingly annual New Year’s weight loss resolution gives as much as a 20 percent boost to Anytime Fitness in Forsyth County, said manager Benjamin Bradley. “I think they like to leave their possible failed attempts at fitness in the previous year and like to think of the new year as a brand new start,” he said.