The project manager should put in place a time and materials contract before work begins for a third party that needs to perform a short-term task for which the duration cannot be accurately estimated and the cost cannot be calculated in advance. A time and materials contract is a type of contract where the buyer pays the seller based on the actual time spent and materials used during the project. A time and materials contract is suitable for projects that have uncertain or variable scope, duration, or cost. A time and materials contract can provide flexibility and adaptability for both parties and allow them to adjust to changing requirements or circumstances.