You return to a draft and cannot remember why the opening changed. Was the earlier version unclear, or did you simply prefer a new sentence that day? A short revision log preserves the reason without recording every comma.
Use three fields
Write the problem, the change and the result you want to check. For example: “The main question arrives late; moved the concrete example to the opening; ask whether the purpose is now clear.” This is an illustrative entry, not a report of a tested revision.
Keep entries for structural or meaningful changes. Logging every minor correction can make the record harder to use than the draft itself.
Distinguish the attempt from the outcome
“Moved the example” records an action. “The opening is clearer” is a judgment that still needs a reading. Leave room to add feedback or your own later assessment.
If the change fails, record what remained confusing. A failed experiment can still save time by showing which explanation did not solve the problem.
Review a small set of decisions
Before another major revision, read the last few entries. Are you repeatedly moving the same material because the central question is unresolved? The log may reveal that pattern more clearly than another line edit.
For the next decision, use a specific feedback request. A revision log is most useful when it connects a concrete problem with a checkable change, while leaving the finished piece free of the process notes behind it.