I have been in business for 10 years and I have made a lot of contacts in regard to contractors, lawn services, excavators, glass installers, etc. It has been very valuable to my clients over the years as I have referred so many. I make sure I use each and every one of my contacts prior to referring them to my clients. Their work reflects on my judgment which I take very seriously. 

Before you refer a worker to your source of bread and butter, make sure you have experienced or someone you value has experienced the work of the contractor. I am amazed at how many talented people there are out there and how valuable it is to me and my clients to keep in touch with them. Not only do you maintain valuable friendships and contacts, you earn their respect and discounts which are forwarded onto you when needed. If by any chance you can't refer someone that is needed, nor can you find someone who is reliable through other sources, be honest with your client and let them know. You certainly don't want to be responsible for a job NOT well done. 

Also, give your contractors the respect by putting their name and service on your web site. This offers them recognition, future references for your clients and a Rolodex per say for anyone to refer back to.