As a sales engineer, your responsibilities are to serve as a technical advisor to prospective clients. Your duties may include helping customers decide what to buy for a project, demonstrating the use of products, providing instruction and support, and even performing installations. Companies typically ask sales engineers to sell complex technological or scientific products, which requires extensive knowledge of the parts and functions of each product, as well as related processes. You may also be asked to travel on a regular basis, present information to large crowds, or work irregular hours to meet sales goals and the needs of clients.