What is due diligence? Due diligence is important as it allows you to learn about the financial health, operations, and potential issues such as outstanding legal claims against the business you are looking to buy. Once you purchase a business, you’ll become responsible for any problems, including debt and legal claims. Therefore, due diligence is often critical. The following is a sample due diligence request list that can be adjusted for any size business acquisition. Consultation with an attorney or CPA is recommended.