If you ever have to move from a single prototype to machine assembly using automatic pick and place machines, you’re most likely going to have to deal with panelizing your PCBs.  This just means taking your basic PCB design, and multiplying it a certain numbers of time in an X/Y pattern.  What happens is the machine operator will program one board in, and they can simply step and repeat across all the other boards on the panel, significantly speeding up assembly since solder paste can be applied to many boards at once, and minimizing time lost shifting boards in and out of the pick and place.  While there’s some information out there on the panelization process, it’s not spoken about nearly as much as it could be, which is why I was glad to come across this article (from the very read worthy Printed Circuit Design & Fab): The PCB Array, and Why We Use It.  Definately do some more digging around on that site if you’re into PCB design, since there’s a lot of great stuff and you can browse back issues online for free!