ok, this is how I think about about what muscle groups to train on each day...well just a few, anyway
Alright, when working Chest, Doesn't it make sence to also work tricepts the same day since they are basically being utilized heavily during Bench/dumbell presses anyway?
Also, To work Bicepts the same day as back since it once again is being utilized heavily when doing Pullups/Pulldowns, rows...etc?
Seems more effective than a system of back then chest then arms day(in any order)
this is always how I've organized things for the past 8 years...if i'm doing it all wrong, oh well, it works for me