Choosing a different writer for every project is self defeating. Perhaps you save some pocket change by selecting the lowest bidder but you waste valuable time acquainting each candidate with your business model. Moreover, your written communications become a patchwork of style and voice. It shows.
Think about it for a moment – would you ask for bids from your vendors, accountant and attorney every time you needed something from them? You recognize the investment in research and time getting acquainted with you – it’s no different with a writer.
In fact, I was a CPA in a former life and I can tell you – without fear of contradiction – that I was able to serve my client base more effectively because I had already invested the time to understand their business. We didn’t waste time rehashing the preliminaries at every meeting.
Furthermore, after you’ve approved a few assignments (with feedback, if necessary), you can rest assured that a committed writer will take the initiative to suggest their own subjects for your consideration.