This is a really interesting topic to discuss. There are many pros and cons of having a written agreement versus verbal agreement. Many medical device companies execute a supplier quality agreement with the suppliers on their approved supplier list (ASL). This is a legal written agreement detailing the terms and conditions of the customer to the supplier acceptance criteria of the products. In addition, there may be a challenge to have this execute with the supplier and can be time consuming. At this point, verbal agreement can be useful, but there is a risk involved as there is no documented evidence of the agreed terms and conditions. Due to time constraints, one can start the project on a risk based approach, however it is highly recommended to draft and execute a written agreement.