Document Retention for PO and Agreements

Summary:

Currently there is no ability to delete an Open Purchase Order or Agreement, a user is only able to cancel or close those documents. Is there a retention policy for these documents and attachments on those purchasing documents or are they retained in perpetuity?

Due to statutes my client is concerned that these documents could be deleted either manually by a user or on the back end and would like to ensure they will have access to these documents and attachments. Unfortunately, I cannot find any documentation around these retention policies if there are any.

Content (please ensure you mask any confidential information):