Vendor management is not a science, but a straightforward approach that could be applied by literally any company. Unfortunately, nowadays most companies are driven by a short-term, you may also call it short-sighted, mainly cost-driven approach. This works for non-strategic products and services, for which you easily could swap suppliers.
Any service, product or good that is strategic for your company requires a different approach how to deal with your suppliers. Have a look at those 8 tips for a successful vendor management.