hey guys i need some help coming up with a new work out.. as of now i am usally doing 3 days on 1 day off.. i do chest tri/ back bis/ shoulders legs.. i wanna change things up a bit i have been doing thois same routine for a while now.. any sugestions would be a great help// i waas thinking about doing arms all together one day .. is this a good idea? and how many times a week should i be doing chest and back ? and should i have light and heavy days mixed in?