Hire them on contingency, and then verify their results. Use something like http://zoomrank.com/ http://zoomrank.com/ to monitor the position of your site in t

Hire them on contingency, and then verify their results. Use something like http://zoomrank.com/ http://zoomrank.com/ to monitor the position of your site in the various search engines over time; establish a baseline, hire the SEO consultant, and look at your placement graphs. Did you fail to improve, or even go down? Then don't pay the snake oil salesman.