For you fellas who said once a week, is it really only once a week? If u train on a split that has an arms day, then your arms are getting trained twice a week, and if u have an arm day, a chest day, and a delt day, then your tris are getting trained 3 times a week, so its most likely that the fellas who said that they train each part once a week are really only training legs and bacl once a week.