Someone looks at the cost to produce cleaner data, and where this line croses the cost of delaying the mailing. At that point, it's "good enough." I strongly suspect most decisions don't have nearly this clear a metric by which to define "good enough," yet the call is made anyway.

Beyond that, my comments were more directed to the process than the actual decision. If, as I said, someone is willing to trust a project to a wet, pink newbie they have just proven through action that they don't really think it's that important. You are obviously not a newbie (though I won't comment on your pinkness or wetness). They are willing to pay for you. When they give your job to a PFY to save money, that's when "good enough" is a fool's bargain.