What are some ways that the project team members, project managers, and the organization can use lessons learned?

Why it is important to close out a project even if the project was closed early by management?
Why should Project Managers capture lessons learned?
What are some ways that the project team members, project managers, and the organization can use lessons learned?
What benefits come from celebrating project accomplishments? Do you believe that rewards and recognition can serve as motivators for staff?
If you are running an Agile project when are lessons learned captured?
APA format 500 words