* Cost: Good experienced devs in a timezone I want to be awake for to talk with cost more than I can afford to pay (generalizing here)
* Management overhead: Good communication, writing good specs, etc such that a dev can complete the work in the way I want it done can be just as time consuming if not more so than doing it myself
* Establishing trust: Farming out work when in crunch mode to an unproven dev and hoping for the best doesn't sit well with me. I would want to establish a working relationship starting with code projects that are small and don't care if they come back crappy (which is almost none of my work at the moment)
* NDAs: Companies generally don't like you granting access to their codebase to people they did not vet/hire themselves