IMO your workout regimen should be tailored to your own situation and body dimensions. For example for me I could get away with working out back only once a week because it's my strong point. I naturally have a wide thick back so overworking it would throw my proportions off. I also like to give arms their own day, along with the inadvertent work they do on push and pull days. For chest, if I can I'll do twice a week to keep up with my back and so far it's been working for me. To my understanding bodybuilding is just that; building your body , and like with any build or construction, no blueprint is the same because not every terrain is the same. For me proportions are important as much as size and IMO it makes no sense to follow a preset workout regimen when we have all different terrains to work with.
