Why not self-edit?
It's not easy to pick up errors in one's own writing or in material that we have read again and again.
The problem is that when our target audience picks up errors or inconsistencies, they begin to question the quality of the product or the credibility and expertise of the service provider.
So what we put out there can directly impact our response rate and hence our bottom line.
Which means it is well worth employing a professional who makes the effort to understand our aims and obectives and who will help to ensure that the quality of our written material matches that of our products and services. To help you make a choice, read my references and more about my experience.