A Retainer Agreement is a contract between a client and a service provider, often a lawyer or consultant, where the client pays a fee in advance for services to be rendered over a specific period. This arrangement ensures that the service provider is available to the client when needed, providing a sense of security and commitment. These agreements typically outline the scope of services, payment terms, and duration of the engagement. They help clarify expectations and responsibilities for both parties, making it easier to manage ongoing projects or legal matters without the need for constant negotiations.