First, the instructions:  very clear, language-neutral illustrations for each and every step.  Second, the components: using the principal of “self-guided assembly,” the parts (framing, sheathing, finishes, etc. – all of which will weigh under 23lbs) actually interlock with each other, removing the need for multiple people or bracing to hold things plumb and square, as well as dramatically reducing the possibility of incorrect assembly.  Third, the completeness:  everything is there, clearly labeled, pilot-drilled, and packaged such that the first part is on top, the last part is on the bottom.  Finally, the tools:  all that is needed is a cordless drill and a rubber mallet (and, in some cases, a step ladder); everything is screwed together into pre-existing pilot holes, everything is cut to exact sizes (no tape measures and no dangerous saws!), and everything interlocks (no levels – the interlocking makes it plumb and square!).  (Note:  Modification and addition projects to existing buildings may require other tools, but we’ll help you keep those to a minimum.).