Updating your testimonials and references
Your testimonials must be current, compelling and credible! Prospects want to know if your products and services work in today’s marketplace – not the one from five or 10 years ago.
Source: Sales consultant Colleen Francis
This point applies similarly to references. You can’t reinforce your "social proof" in the eyes of prospects if your references can’t be reached, are retired, or simply shouldn’t be references at all. Find new references from your current clients.
And do it regularly.