I agree with Dan Wood about using a separate build directory. Not only do you keep the build junk out of the source directory, but if you plan on using any of Xcode's project-dependency features, a mutually shared build directory is a necessity. I've found like to be a lot better with a generally shared build directory. The one thing to look out for is if you've got more than one project that build the same framework, but at different versions, for instance. Then you'll need to be sure that you do a full clean when switching between them.