I have seen people do this before, and it makes a lot of sense. On the other hand, I have my nine tattoos on every category of body parts except my left arm and back, and the most tattoos I have on any particular appendage is two. I like having it that way, for a variety of reasons. I plan on eventually having a body suit, so I figure I might as well get a mix of larger and smaller, one or two session tattoos. My backpiece will take place when I have enough money and the right idea, and my left arm is saved for a Japanese sleeve.