A number becomes more useful when another person can understand where it came from.
Keep the source identifiable
Give the original document a stable reference. Record the site, supplier, period and activity it supports. Keep the original unit even when you also store a converted value.
Make transformations visible
If an invoice covers two reporting periods, record how the quantity was allocated. If a calculation uses an emission factor, retain the factor source, version and unit. Explain which method applies and why it was selected.
Separate preparation from approval
The person collecting a record may not be the person approving its use. Keep those responsibilities visible and preserve unresolved questions. Review status should tell a later reader what has actually been checked.
Carry context into the output
A disclosure working pack should let reviewers follow a figure back to the supporting record. It should also make clear whether the value is reported, estimated or derived, and whether the reporting boundary has changed.