Hello,
Very good question. I have clients that ask me this as well.
I like to tailor my massage to my client's needs. So, if I have a client that really needs extra work done in this area I prefer to devote the whole one hour massage to the neck, shouler and the ENTIRE back area so that I can be more muscle specific. I incorporate the arms as well because I like to stretch the pectoral muscles and other back muscles with the arm movements and this releases the whole shoulder area.
To me, doing the rest of the body is more like doing... please excuse the term... a "fluff and buff" massage.
I do get better results and my clients agree that it helps them a great deal. Some clients, upon returning for another massage, start requesting that I totally focus on these areas and leave out the lower extremities.
So, that was a long answer to your question. One hour would be sufficient. But, if you want the full body you might want to go for 1.5 hour with the major focus being neck, shoulders & entire back.
Hope this has helped you make a decision.
Namaste,
Hermene Anderson, LMT