A Time and Materials Contract is an agreement between a client and a contractor where the client pays for the actual time spent on a project and the materials used. This type of contract is often used in construction and consulting, allowing flexibility in project scope and changes. The contractor bills the client based on hourly rates and the cost of materials, which can help manage unpredictable project requirements. This contract is beneficial when project details are not fully defined at the start. It allows for adjustments as work progresses, making it easier to accommodate changes without the need for extensive renegotiation. However, clients should monitor costs closely to avoid unexpected expenses.