“How effective are these listing sites? That’s the million dollar question, it’s a hit and miss proposition, you have to track each listing sites performance to make a determination.”
Concur 
percent with @cfletcher 's statement above . . . as it mirrors my direct experience over an interval of more than a decade.
Here are a few helpful insights:
- Marketing is required to have a successful business
- Marketing costs can be expensive
- The Return on Investment [ROI] is a determination that ONLY you can make for your region & your business AFTER you’ve compiled the data from the results of marketing your professional services
- It’s IMPORTANT to pose the following query to your clients/potential clients : “How did you find me?” ===>>> WHY QUERY? Because it’s information that you need & information that is 'not important’ to your clients/potential clients. So, you must ASK for it!
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You may also find additional helpful information in this separate thread:
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